What is the most aerodynamic Satellite?
$begingroup$
From what I understand at least in the lower orbits you want the least amount of drag possible.
My brain is telling me that a long pole or submarine shape satellite orientated to the direction of travel or direction of solar wind would be best and not a ball at all?
At what point does the extra weight and mass to make a satellite aerodynamic cost more fuel then saved?
artificial-satellite design aerodynamics drag
asked Dec 30 '18 at 18:14
MuzeMuze
1,4701368
$endgroup$
|
show 3 more comments
$begingroup$
From what I understand at least in the lower orbits you want the least amount of drag possible.
My brain is telling me that a long pole or submarine shape satellite orientated to the direction of travel or direction of solar wind would be best and not a ball at all?
At what point does the extra weight and mass to make a satellite aerodynamic cost more fuel then saved?
artificial-satellite design aerodynamics drag
asked Dec 30 '18 at 18:14
MuzeMuze
1,4701368
$endgroup$
5
$begingroup$
Aerodynamics at a pressure of about 1 bar and subsonic speeds may be very different to drag in a nearly perfect vacuum and at hypersonic orbital speed.
$endgroup$
– Uwe
Dec 30 '18 at 18:40
1
$begingroup$
@Uwe If you released 2 rubber balloons with a .2psi from the bow of the ISS one shaped as a strait noodle balloon and the other round how much would "nearly" effect each balloon?
$endgroup$
– Muze
Dec 30 '18 at 18:47
2
$begingroup$
At theses speed and pressure cross section is all that matter.
$endgroup$
– Antzi
Dec 31 '18 at 8:09
1
$begingroup$
That's not a space plane, @Muze. It would have been a flying brick in the atmosphere. And at 250 km altitude, it was barely in space. The primary driver for the shape was the need for a sizable area for non-moving solar panels.
$endgroup$
– David Hammen
Jan 1 at 5:25
1
$begingroup$
Some like of low orbit satellite. E.g. Kosmos 954 or nuclear satellite in general. The only motivation to go with nuclear power is to improve aerodynamics.
$endgroup$
– user3528438
Jan 2 at 6:05
|
show 3 more comments
$begingroup$
From what I understand at least in the lower orbits you want the least amount of drag possible.
My brain is telling me that a long pole or submarine shape satellite orientated to the direction of travel or direction of solar wind would be best and not a ball at all?
At what point does the extra weight and mass to make a satellite aerodynamic cost more fuel then saved?
artificial-satellite design aerodynamics drag
asked Dec 30 '18 at 18:14
MuzeMuze
1,4701368
$endgroup$
From what I understand at least in the lower orbits you want the least amount of drag possible.
My brain is telling me that a long pole or submarine shape satellite orientated to the direction of travel or direction of solar wind would be best and not a ball at all?
At what point does the extra weight and mass to make a satellite aerodynamic cost more fuel then saved?
artificial-satellite design aerodynamics drag
artificial-satellite design aerodynamics drag
asked Dec 30 '18 at 18:14
MuzeMuze
1,4701368
asked Dec 30 '18 at 18:14
MuzeMuze
1,4701368
edited Dec 31 '18 at 18:23
Muze
asked Dec 30 '18 at 18:14
MuzeMuze
1,4701368
asked Dec 30 '18 at 18:14
MuzeMuze
1,4701368
asked Dec 30 '18 at 18:14
MuzeMuze
1,4701368
1,4701368
5
$begingroup$
Aerodynamics at a pressure of about 1 bar and subsonic speeds may be very different to drag in a nearly perfect vacuum and at hypersonic orbital speed.
$endgroup$
– Uwe
Dec 30 '18 at 18:40
1
$begingroup$
@Uwe If you released 2 rubber balloons with a .2psi from the bow of the ISS one shaped as a strait noodle balloon and the other round how much would "nearly" effect each balloon?
$endgroup$
– Muze
Dec 30 '18 at 18:47
2
$begingroup$
At theses speed and pressure cross section is all that matter.
$endgroup$
– Antzi
Dec 31 '18 at 8:09
1
$begingroup$
That's not a space plane, @Muze. It would have been a flying brick in the atmosphere. And at 250 km altitude, it was barely in space. The primary driver for the shape was the need for a sizable area for non-moving solar panels.
$endgroup$
– David Hammen
Jan 1 at 5:25
1
$begingroup$
Some like of low orbit satellite. E.g. Kosmos 954 or nuclear satellite in general. The only motivation to go with nuclear power is to improve aerodynamics.
$endgroup$
– user3528438
Jan 2 at 6:05
|
show 3 more comments
5
$begingroup$
Aerodynamics at a pressure of about 1 bar and subsonic speeds may be very different to drag in a nearly perfect vacuum and at hypersonic orbital speed.
$endgroup$
– Uwe
Dec 30 '18 at 18:40
1
$begingroup$
@Uwe If you released 2 rubber balloons with a .2psi from the bow of the ISS one shaped as a strait noodle balloon and the other round how much would "nearly" effect each balloon?
$endgroup$
– Muze
Dec 30 '18 at 18:47
2
$begingroup$
At theses speed and pressure cross section is all that matter.
$endgroup$
– Antzi
Dec 31 '18 at 8:09
1
$begingroup$
That's not a space plane, @Muze. It would have been a flying brick in the atmosphere. And at 250 km altitude, it was barely in space. The primary driver for the shape was the need for a sizable area for non-moving solar panels.
$endgroup$
– David Hammen
Jan 1 at 5:25
1
$begingroup$
Some like of low orbit satellite. E.g. Kosmos 954 or nuclear satellite in general. The only motivation to go with nuclear power is to improve aerodynamics.
$endgroup$
– user3528438
Jan 2 at 6:05
5
5
$begingroup$
Aerodynamics at a pressure of about 1 bar and subsonic speeds may be very different to drag in a nearly perfect vacuum and at hypersonic orbital speed.
$endgroup$
– Uwe
Dec 30 '18 at 18:40
$begingroup$
Aerodynamics at a pressure of about 1 bar and subsonic speeds may be very different to drag in a nearly perfect vacuum and at hypersonic orbital speed.
$endgroup$
– Uwe
Dec 30 '18 at 18:40
1
1
$begingroup$
@Uwe If you released 2 rubber balloons with a .2psi from the bow of the ISS one shaped as a strait noodle balloon and the other round how much would "nearly" effect each balloon?
$endgroup$
– Muze
Dec 30 '18 at 18:47
$begingroup$
@Uwe If you released 2 rubber balloons with a .2psi from the bow of the ISS one shaped as a strait noodle balloon and the other round how much would "nearly" effect each balloon?
$endgroup$
– Muze
Dec 30 '18 at 18:47
2
2
$begingroup$
At theses speed and pressure cross section is all that matter.
$endgroup$
– Antzi
Dec 31 '18 at 8:09
$begingroup$
At theses speed and pressure cross section is all that matter.
$endgroup$
– Antzi
Dec 31 '18 at 8:09
1
1
$begingroup$
That's not a space plane, @Muze. It would have been a flying brick in the atmosphere. And at 250 km altitude, it was barely in space. The primary driver for the shape was the need for a sizable area for non-moving solar panels.
$endgroup$
– David Hammen
Jan 1 at 5:25
$begingroup$
That's not a space plane, @Muze. It would have been a flying brick in the atmosphere. And at 250 km altitude, it was barely in space. The primary driver for the shape was the need for a sizable area for non-moving solar panels.
$endgroup$
– David Hammen
Jan 1 at 5:25
1
1
$begingroup$
Some like of low orbit satellite. E.g. Kosmos 954 or nuclear satellite in general. The only motivation to go with nuclear power is to improve aerodynamics.
$endgroup$
– user3528438
Jan 2 at 6:05
$begingroup$
Some like of low orbit satellite. E.g. Kosmos 954 or nuclear satellite in general. The only motivation to go with nuclear power is to improve aerodynamics.
$endgroup$
– user3528438
Jan 2 at 6:05
|
show 3 more comments
1 Answer
1
active
oldest
votes
$begingroup$
The only satellite I know of that was shaped to have low drag was GOCE, which orbited at 250 km.
Since it was vital to ensure that the measurements taken are of true gravity and not influenced by any movement of the satellite, this unique five-metre long arrow-shaped satellite had none of the moving parts often seen in other spacecraft. The satellite, together with its instrumentation, actually forms a single composite gravity-measuring device.
The satellite orbited Earth as low as possible to observe the strongest possible gravity-field signal – hence GOCE was designed to skim the edge of Earth's atmosphere at a height of about 250 km. Low fuel consumption meant that its altitude could be lowered to 235 km in 2012.
An electric ion thruster at the back of the satellite continuously generated tiny forces to compensate for any drag that GOCE experienced along its orbit.
The need to fly low and be ultra-stable led to a novel satellite design that minimised air drag and torque and excludes mechanical disturbances. The result was a slim 5 metre-long satellite with a cross sectional area of about 1m2, weighing in at about 1050 kg. The satellite was symmetrical about its horizontal plane and had two winglets that provided additional aerodynamic stability.
You can see this places constraints on the satellite's shape: you can't have protruding solar panels, antennas etc. This means it's only done when really necessary; for most purposes it's much cheaper to go to a slightly higher orbit instead.
answered Dec 30 '18 at 19:30
HobbesHobbes
96.6k2272427
$endgroup$
$begingroup$
That's very cool and new to me.
$endgroup$
– Organic Marble
Dec 30 '18 at 20:59
$begingroup$
The solar panels are built into it as shown and an antenna follows the wings. The space craft is on a lean performing a turn the belly facing towards the camera.
$endgroup$
– Muze
Dec 30 '18 at 21:30
$begingroup$
@Muze Sorry about that... try: GRACE
$endgroup$
– costrom
Dec 31 '18 at 15:18
$begingroup$
This would answer another question I have. space.stackexchange.com/questions/33087/…
$endgroup$
– Muze
Dec 31 '18 at 18:28
1
$begingroup$
Fin stabilizers, in orbit? Neat, it's literally a spaceplane.
$endgroup$
– Mazura
Dec 31 '18 at 20:15
|
show 1 more comment
Your Answer
StackExchange.ready(function() {
var channelOptions = {
tags: "".split(" "),
id: "508"
};
initTagRenderer("".split(" "), "".split(" "), channelOptions);
StackExchange.using("externalEditor", function() {
// Have to fire editor after snippets, if snippets enabled
if (StackExchange.settings.snippets.snippetsEnabled) {
StackExchange.using("snippets", function() {
createEditor();
});
}
else {
createEditor();
}
});
function createEditor() {
StackExchange.prepareEditor({
heartbeatType: 'answer',
autoActivateHeartbeat: false,
convertImagesToLinks: false,
noModals: true,
showLowRepImageUploadWarning: true,
reputationToPostImages: null,
bindNavPrevention: true,
postfix: "",
imageUploader: {
brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
allowUrls: true
},
noCode: true, onDemand: true,
discardSelector: ".discard-answer"
,immediatelyShowMarkdownHelp:true
});
}
});
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fspace.stackexchange.com%2fquestions%2f33198%2fwhat-is-the-most-aerodynamic-satellite%23new-answer', 'question_page');
}
);
Post as a guest
Required, but never shown
1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
$begingroup$
The only satellite I know of that was shaped to have low drag was GOCE, which orbited at 250 km.
Since it was vital to ensure that the measurements taken are of true gravity and not influenced by any movement of the satellite, this unique five-metre long arrow-shaped satellite had none of the moving parts often seen in other spacecraft. The satellite, together with its instrumentation, actually forms a single composite gravity-measuring device.
The satellite orbited Earth as low as possible to observe the strongest possible gravity-field signal – hence GOCE was designed to skim the edge of Earth's atmosphere at a height of about 250 km. Low fuel consumption meant that its altitude could be lowered to 235 km in 2012.
An electric ion thruster at the back of the satellite continuously generated tiny forces to compensate for any drag that GOCE experienced along its orbit.
The need to fly low and be ultra-stable led to a novel satellite design that minimised air drag and torque and excludes mechanical disturbances. The result was a slim 5 metre-long satellite with a cross sectional area of about 1m2, weighing in at about 1050 kg. The satellite was symmetrical about its horizontal plane and had two winglets that provided additional aerodynamic stability.
You can see this places constraints on the satellite's shape: you can't have protruding solar panels, antennas etc. This means it's only done when really necessary; for most purposes it's much cheaper to go to a slightly higher orbit instead.
answered Dec 30 '18 at 19:30
HobbesHobbes
96.6k2272427
$endgroup$
$begingroup$
That's very cool and new to me.
$endgroup$
– Organic Marble
Dec 30 '18 at 20:59
$begingroup$
The solar panels are built into it as shown and an antenna follows the wings. The space craft is on a lean performing a turn the belly facing towards the camera.
$endgroup$
– Muze
Dec 30 '18 at 21:30
$begingroup$
@Muze Sorry about that... try: GRACE
$endgroup$
– costrom
Dec 31 '18 at 15:18
$begingroup$
This would answer another question I have. space.stackexchange.com/questions/33087/…
$endgroup$
– Muze
Dec 31 '18 at 18:28
1
$begingroup$
Fin stabilizers, in orbit? Neat, it's literally a spaceplane.
$endgroup$
– Mazura
Dec 31 '18 at 20:15
|
show 1 more comment
$begingroup$
The only satellite I know of that was shaped to have low drag was GOCE, which orbited at 250 km.
Since it was vital to ensure that the measurements taken are of true gravity and not influenced by any movement of the satellite, this unique five-metre long arrow-shaped satellite had none of the moving parts often seen in other spacecraft. The satellite, together with its instrumentation, actually forms a single composite gravity-measuring device.
The satellite orbited Earth as low as possible to observe the strongest possible gravity-field signal – hence GOCE was designed to skim the edge of Earth's atmosphere at a height of about 250 km. Low fuel consumption meant that its altitude could be lowered to 235 km in 2012.
An electric ion thruster at the back of the satellite continuously generated tiny forces to compensate for any drag that GOCE experienced along its orbit.
The need to fly low and be ultra-stable led to a novel satellite design that minimised air drag and torque and excludes mechanical disturbances. The result was a slim 5 metre-long satellite with a cross sectional area of about 1m2, weighing in at about 1050 kg. The satellite was symmetrical about its horizontal plane and had two winglets that provided additional aerodynamic stability.
You can see this places constraints on the satellite's shape: you can't have protruding solar panels, antennas etc. This means it's only done when really necessary; for most purposes it's much cheaper to go to a slightly higher orbit instead.
answered Dec 30 '18 at 19:30
HobbesHobbes
96.6k2272427
$endgroup$
$begingroup$
That's very cool and new to me.
$endgroup$
– Organic Marble
Dec 30 '18 at 20:59
$begingroup$
The solar panels are built into it as shown and an antenna follows the wings. The space craft is on a lean performing a turn the belly facing towards the camera.
$endgroup$
– Muze
Dec 30 '18 at 21:30
$begingroup$
@Muze Sorry about that... try: GRACE
$endgroup$
– costrom
Dec 31 '18 at 15:18
$begingroup$
This would answer another question I have. space.stackexchange.com/questions/33087/…
$endgroup$
– Muze
Dec 31 '18 at 18:28
1
$begingroup$
Fin stabilizers, in orbit? Neat, it's literally a spaceplane.
$endgroup$
– Mazura
Dec 31 '18 at 20:15
|
show 1 more comment
$begingroup$
The only satellite I know of that was shaped to have low drag was GOCE, which orbited at 250 km.
Since it was vital to ensure that the measurements taken are of true gravity and not influenced by any movement of the satellite, this unique five-metre long arrow-shaped satellite had none of the moving parts often seen in other spacecraft. The satellite, together with its instrumentation, actually forms a single composite gravity-measuring device.
The satellite orbited Earth as low as possible to observe the strongest possible gravity-field signal – hence GOCE was designed to skim the edge of Earth's atmosphere at a height of about 250 km. Low fuel consumption meant that its altitude could be lowered to 235 km in 2012.
An electric ion thruster at the back of the satellite continuously generated tiny forces to compensate for any drag that GOCE experienced along its orbit.
The need to fly low and be ultra-stable led to a novel satellite design that minimised air drag and torque and excludes mechanical disturbances. The result was a slim 5 metre-long satellite with a cross sectional area of about 1m2, weighing in at about 1050 kg. The satellite was symmetrical about its horizontal plane and had two winglets that provided additional aerodynamic stability.
You can see this places constraints on the satellite's shape: you can't have protruding solar panels, antennas etc. This means it's only done when really necessary; for most purposes it's much cheaper to go to a slightly higher orbit instead.
answered Dec 30 '18 at 19:30
HobbesHobbes
96.6k2272427
$endgroup$
The only satellite I know of that was shaped to have low drag was GOCE, which orbited at 250 km.
Since it was vital to ensure that the measurements taken are of true gravity and not influenced by any movement of the satellite, this unique five-metre long arrow-shaped satellite had none of the moving parts often seen in other spacecraft. The satellite, together with its instrumentation, actually forms a single composite gravity-measuring device.
The satellite orbited Earth as low as possible to observe the strongest possible gravity-field signal – hence GOCE was designed to skim the edge of Earth's atmosphere at a height of about 250 km. Low fuel consumption meant that its altitude could be lowered to 235 km in 2012.
An electric ion thruster at the back of the satellite continuously generated tiny forces to compensate for any drag that GOCE experienced along its orbit.
The need to fly low and be ultra-stable led to a novel satellite design that minimised air drag and torque and excludes mechanical disturbances. The result was a slim 5 metre-long satellite with a cross sectional area of about 1m2, weighing in at about 1050 kg. The satellite was symmetrical about its horizontal plane and had two winglets that provided additional aerodynamic stability.
You can see this places constraints on the satellite's shape: you can't have protruding solar panels, antennas etc. This means it's only done when really necessary; for most purposes it's much cheaper to go to a slightly higher orbit instead.
answered Dec 30 '18 at 19:30
HobbesHobbes
96.6k2272427
answered Dec 30 '18 at 19:30
HobbesHobbes
96.6k2272427
answered Dec 30 '18 at 19:30
HobbesHobbes
96.6k2272427
answered Dec 30 '18 at 19:30
HobbesHobbes
96.6k2272427
96.6k2272427
$begingroup$
That's very cool and new to me.
$endgroup$
– Organic Marble
Dec 30 '18 at 20:59
$begingroup$
The solar panels are built into it as shown and an antenna follows the wings. The space craft is on a lean performing a turn the belly facing towards the camera.
$endgroup$
– Muze
Dec 30 '18 at 21:30
$begingroup$
@Muze Sorry about that... try: GRACE
$endgroup$
– costrom
Dec 31 '18 at 15:18
$begingroup$
This would answer another question I have. space.stackexchange.com/questions/33087/…
$endgroup$
– Muze
Dec 31 '18 at 18:28
1
$begingroup$
Fin stabilizers, in orbit? Neat, it's literally a spaceplane.
$endgroup$
– Mazura
Dec 31 '18 at 20:15
|
show 1 more comment
$begingroup$
That's very cool and new to me.
$endgroup$
– Organic Marble
Dec 30 '18 at 20:59
$begingroup$
The solar panels are built into it as shown and an antenna follows the wings. The space craft is on a lean performing a turn the belly facing towards the camera.
$endgroup$
– Muze
Dec 30 '18 at 21:30
$begingroup$
@Muze Sorry about that... try: GRACE
$endgroup$
– costrom
Dec 31 '18 at 15:18
$begingroup$
This would answer another question I have. space.stackexchange.com/questions/33087/…
$endgroup$
– Muze
Dec 31 '18 at 18:28
1
$begingroup$
Fin stabilizers, in orbit? Neat, it's literally a spaceplane.
$endgroup$
– Mazura
Dec 31 '18 at 20:15
$begingroup$
That's very cool and new to me.
$endgroup$
– Organic Marble
Dec 30 '18 at 20:59
$begingroup$
That's very cool and new to me.
$endgroup$
– Organic Marble
Dec 30 '18 at 20:59
$begingroup$
The solar panels are built into it as shown and an antenna follows the wings. The space craft is on a lean performing a turn the belly facing towards the camera.
$endgroup$
– Muze
Dec 30 '18 at 21:30
$begingroup$
The solar panels are built into it as shown and an antenna follows the wings. The space craft is on a lean performing a turn the belly facing towards the camera.
$endgroup$
– Muze
Dec 30 '18 at 21:30
$begingroup$
@Muze Sorry about that... try: GRACE
$endgroup$
– costrom
Dec 31 '18 at 15:18
$begingroup$
@Muze Sorry about that... try: GRACE
$endgroup$
– costrom
Dec 31 '18 at 15:18
$begingroup$
This would answer another question I have. space.stackexchange.com/questions/33087/…
$endgroup$
– Muze
Dec 31 '18 at 18:28
$begingroup$
This would answer another question I have. space.stackexchange.com/questions/33087/…
$endgroup$
– Muze
Dec 31 '18 at 18:28
1
1
$begingroup$
Fin stabilizers, in orbit? Neat, it's literally a spaceplane.
$endgroup$
– Mazura
Dec 31 '18 at 20:15
$begingroup$
Fin stabilizers, in orbit? Neat, it's literally a spaceplane.
$endgroup$
– Mazura
Dec 31 '18 at 20:15
|
show 1 more comment
Thanks for contributing an answer to Space Exploration Stack Exchange!
- Please be sure to answer the question. Provide details and share your research!
But avoid …
- Asking for help, clarification, or responding to other answers.
- Making statements based on opinion; back them up with references or personal experience.
Use MathJax to format equations. MathJax reference.
To learn more, see our tips on writing great answers.
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fspace.stackexchange.com%2fquestions%2f33198%2fwhat-is-the-most-aerodynamic-satellite%23new-answer', 'question_page');
}
);
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
5
$begingroup$
Aerodynamics at a pressure of about 1 bar and subsonic speeds may be very different to drag in a nearly perfect vacuum and at hypersonic orbital speed.
$endgroup$
– Uwe
Dec 30 '18 at 18:40
1
$begingroup$
@Uwe If you released 2 rubber balloons with a .2psi from the bow of the ISS one shaped as a strait noodle balloon and the other round how much would "nearly" effect each balloon?
$endgroup$
– Muze
Dec 30 '18 at 18:47
2
$begingroup$
At theses speed and pressure cross section is all that matter.
$endgroup$
– Antzi
Dec 31 '18 at 8:09
1
$begingroup$
That's not a space plane, @Muze. It would have been a flying brick in the atmosphere. And at 250 km altitude, it was barely in space. The primary driver for the shape was the need for a sizable area for non-moving solar panels.
$endgroup$
– David Hammen
Jan 1 at 5:25
1
$begingroup$
Some like of low orbit satellite. E.g. Kosmos 954 or nuclear satellite in general. The only motivation to go with nuclear power is to improve aerodynamics.
$endgroup$
– user3528438
Jan 2 at 6:05