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Questions tagged [hubble]

The Hubble Space Telescope (HST) is a space telescope in low Earth orbit with a 2.4 meter main mirror capable of observing near ultraviolet, visible, and near infrared light. It was launched in 1990 and remains in operation (following five servicing missions) as of 2015.

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Hubble gyro manufacturer

I have been trying to find information on Hubble's gyros. So far all I have found is that they are rotating mass rate gyros with gas bearings and that the were the most accurate available when ...
John McCarthy's user avatar
21 votes
1 answer
4k views

What is the goal of the message “astronaut use only” written on one Hubble's module?

On the following image, why is it written “astronaut use only”? Since this power control unit is in space, it can only be used by astronauts. So why write this message? Cropped from this image: ...
A.L - say no to AI's user avatar
17 votes
2 answers
2k views

HST can apparently operate in one-gyro mode, if need be. Why was the Compton Gamma Ray Observatory de-orbited when it lost one of its three gyros?

If HST has been reduced to 2 fully functioning gyros, I read that they plan to turn off one gyro and run in single-gyro mode to save the second functioning gyro. The Compton Gamma Ray Observatory had ...
Peter Milne's user avatar
19 votes
3 answers
5k views

Why is the aperture door of the Hubble Space Telescope so weirdly shaped?

Why is the door not rounder? I understand it's main purpose is to block sunlight from entering the telescope. Especially the right side (in the provided image) seems to waste material. But also the ...
felixmp's user avatar
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1 vote
1 answer
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What is a spectral shift?

I have to research this topic for a school project and nothing is showing up other than redshifts and blueshifts and Doppler shifts. Are these all under the spectral shift category? Is a spectral ...
1234's user avatar
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9 votes
1 answer
976 views

What are those yellow trussed structures on Hubble Space Telescope?

Search as I might, I couldn't find them labeled on any schematic or mentioned in any fact sheet. My guess is Shuttle bay interface/attachment, but I also could not corroborate it by searching ...
ymb1's user avatar
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21 votes
1 answer
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Would the Space Shuttle have been able to carry the Hubble Space Telescope back to Earth had it been necessary?

The development of the Space Shuttle (STS) and the Hubble Space Telescope (HST) were running in parallel during the 1970s and 1980s. Both plans for STS and HST were announced in the late 1960 and both ...
Ludo's user avatar
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15 votes
2 answers
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What will now happen with Hubble?

The James Webb Telescope just started it’s scientific work. The amazing pictures and information is definitely better than Hubbles. What will now happen with Hubble?
The Rocket fan's user avatar
2 votes
1 answer
334 views

Hubble vs JWST telescope

Can you quantify how much better JWST is compared to Hubble? For instance, from what distance can each "see" (differentiate) a sun-like star? Maybe there are other measures.
user2679290's user avatar
4 votes
2 answers
433 views

Where can I find an up-to-date report on the Hubble Telescope's orbital history and current altitude?

I haven't been able to find a current report on the state of Hubble's orbital decay and I'm hoping someone can direct me to that info. The satellite tracker sites just present an average or estimate ...
numbynumb's user avatar
16 votes
1 answer
2k views

What did the Hubble fix look like?

When Hubble was built, there was a defect in the mirror that caused the images to be blurry. Astronauts then went to install extra optics on the telescope to fix the blurriness. What did these extra ...
usernumber's user avatar
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2 votes
1 answer
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Is it possible to view JWST from Earth or From Hubble Space Telescope?

Being able to view JWST from Far would be a great way to monitor it visually. Considering the large Sun-Shield which is very shiny also, I wander if it is possible to view it from far using Hubble or ...
rezeli's user avatar
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4 votes
1 answer
269 views

Are there chances to get a Hubble + ISS Moon transit picture?

I have seen these cool transit pictures where ISS is transiting the moon ISS is transiting the Sun Hubble is transiting the moon I even saw picture of ISS Sun transit during solar Eclipse Tiangong ...
Ash's user avatar
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7 votes
0 answers
195 views

Is the Hubble Space Telescope on its last legs, or "back to normal"?

Hubble was designed to accommodate regular servicing and equipment upgrades while in orbit. Instruments and limited life items were designed as orbital replacement units. Five servicing missions (SM 1,...
uhoh's user avatar
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8 votes
0 answers
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With an external airlock attached, could Commercial Crew Program spacecraft service Hubble?

Note just to clarify: is not about the requirements of the Commercial Crew Program, it is about the as-built capabilities of Crew Dragon and Starliner (hereafter referred to as CCPS, CCP (not that one)...
Anton Hengst's user avatar
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7 votes
1 answer
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Suppose Hubble needed to be fixed by replacing an accessible module again and NASA called for help, what are the most likely mission proposals?

Background Hubble has had at least a few troubling issues that were resolved from the ground in recent years, a summary can be found in Engadget's NASA struggles to fix a Hubble Space Telescope ...
uhoh's user avatar
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6 votes
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How was the high rate of degradation of Hubble's main mirror initially predicted? Why did it turn out to be lower? Were cosmic rays really a concern?

This answer to How long was the HST initially supposed to work? in Astronomy SE quotes Assessment of Options for Extending the Life of the Hubble Space Telescope: Final Report as follows: Hubble was ...
uhoh's user avatar
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6 votes
1 answer
425 views

Has Hubble ever focused on something close enough that it had to move away from being focused at infinity?

Hubble wouldn't have to change focus for Pranksat to work because Pranksat is cleverly designed to present a virtual image with a focus at infinity. But if the diffraction-limited Hubble wanted to ...
uhoh's user avatar
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14 votes
2 answers
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If we used Hubble, or the James Webb Space Telescope, how good image could we get of the Starman?

I know that this is never going to happen, because those telescopes have much more important things to look for ... But I was just wondering if we still did it, what would the best result look like? ...
Ash's user avatar
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6 votes
1 answer
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What "improvements in technology" allowed the primary mirror of RST (WFIRST) to be less than 1/4 the weight of Hubble's?

The recent NASA press release Primary Mirror for NASA’s Roman Space Telescope Completed states: While it’s the same size as the Hubble Space Telescope’s main mirror, it is less than one-fourth the ...
quinnkenri's user avatar
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7 votes
2 answers
510 views

What exactly gives a larger field of view to the donated "spy" telescopes that NASA may send to Mars? How much larger?

This answer to Could one of the interstellar probes discover Planet IX by accident? links to Space.com's NASA May Launch Donated Spy Satellite Telescope to Mars which says: An unexpected gift The two ...
uhoh's user avatar
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4 votes
7 answers
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Would it have been cheaper and/or faster to put a James Webb-like Space Telescope on a balloon instead of a rocket?

I've just noticed the following items: CNET: NASA to send stadium-size balloon skyward to study the cosmos JPL/NASA News: NASA Mission Will Study the Cosmos With a Stratospheric Balloon Even in 2020 ...
uhoh's user avatar
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0 votes
1 answer
154 views

View the surface of Mars via Hubble

Has the surface of Mars been observed by the mirror of Hubble ? For example, it could be a good idea for humans to be able to see the lovely Curiosity Rover via Hubble from above.
Merlin's user avatar
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1 answer
777 views

Is it possible to control the operation of the Hubble Space Telescope from ground stations?

Is it possible to manage the placement of the telescope mirror in a specific location through the operator, or do we have to randomly view the data reflected to the telescope ?
Merlin's user avatar
  • 49
3 votes
1 answer
210 views

What were the relative orientations of the Hubble Space Telescope's three star cameras, six rate gyros and four reaction wheels optimized for exactly?

Table 3. in paper Hubble Space Telescope Reduced-Gyro Control Law Design, Implementation and On-Orbit Performance; AAS 08-278 found in @OrganicMarble's answer seems to give the unit vectors where the ...
uhoh's user avatar
  • 148k
0 votes
3 answers
478 views

Why do these two Hubble Space Telescope star cameras point in nearly the same direction, and what's the other window for?

The article in Forbes Former Astronauts Share Ways To Cope With Social Distancing & Isolation includes the following image of the Hubble Space Telescope. Question: I believe that those three ...
uhoh's user avatar
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5 votes
1 answer
817 views

Why does this photo of the Hubble Space Telescope look so weird?

Question: Can someone identify this photograph of the Hubble Space Telescope seen as a still in the Los Angeles Times YouTube video Scientists witness huge cosmic crash, find origins of gold, figure ...
uhoh's user avatar
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13 votes
2 answers
452 views

Why did the Hubble telescope have to stay powered on while in storage?

The Wikipedia article on the Hubble telescope mentions that during the aftermath of the Challenger disaster, the telescope had to be stored for a few years until the Space Shuttle launches could be ...
Ludo's user avatar
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7 votes
1 answer
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Does Hubble need to dump momentum of its reaction wheels?

Hubble has no thrusters, but it is large enough to have nontrivial gravity gradient and tidal forces acting on it. This would induce a torque that has to be cancelled by its reaction wheels. If I ...
Michael Stachowsky's user avatar
18 votes
2 answers
3k views

What preparations would Hubble have needed to return in a Shuttle?

This answer states that the Hubble Space Telescope was originally intended to be returned to Earth in a Shuttle. (from shuttle manifest published immediately before the Columbia failure, showing the ...
DrSheldon's user avatar
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1 vote
0 answers
81 views

Why is the Hubble Space Telescope mass increasing? [duplicate]

According to this Youtube video I came to know that the mass of the Hubble space telescope has increased from the time of launch. What is making this mass increment? Are these the debris?
Amar's user avatar
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20 votes
3 answers
3k views

Could Hubble observe the night side of the Moon?

IIUC the Hubble space telescope cannot observe the Sun lit side of the Moon. And Hubble is never pointed closer than 90 degrees towards the Sun. But this still allows for observing the night side of ...
LocalFluff's user avatar
3 votes
1 answer
228 views

Can James Webb see Kuiper Belt Objects like 2014 MU69 (Ultima Thule)?

In this paper, we learned that Hubble is the only telescope in the vicinity of Earth that can detect Ultima Thule directly. Hubble will eventually fail, and will be somewhat replaced by James Webb. ...
PearsonArtPhoto's user avatar
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2 votes
0 answers
276 views

How do Hubble, Compton, Chandra, and Spitzer compare in bytes of data collected?

The Great Observatories is a NASA nickname for the four largest space telescopes to date. Each covers a different portion of the electromagnetic spectrum: The Hubble Space Telescope, the most famous ...
DrSheldon's user avatar
  • 48k
3 votes
1 answer
723 views

Hubble's one-gyro mode; how does it work for attitude control, stabilization, and slewing?

Space.com's Hubble Space Telescope Apparently in 'Safe Mode' After Gyroscope Failure says: "It’s true. Very stressful weekend. Right now HST is in safe mode while we figure out what to do. ...
uhoh's user avatar
  • 148k
13 votes
2 answers
3k views

Could we see someone walking on Mars from Earth?

Can any telescope be capable to see some one walking on Mars? How much time dilation would there be? What is the theoretical best resolution?
Muze's user avatar
  • 1
42 votes
5 answers
11k views

Why are so many space telescopes placed in LEO instead of at Lagrange Points? And why do we hear about Hubble more than any Langrange-orbit telescope?

Here is the list of every space telescope launched by different space agencies - List of space telescopes. Most of the listed telescopes are placed in Lower Earth Orbit (about 95% of them). It's ...
Paran's user avatar
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5 votes
0 answers
453 views

What were Hubble's jerk and jounce limits? Did JWST have the same?

From Wikipedia: In physics, jerk is the rate of change of acceleration; that is, the derivative of acceleration with respect to time, and as such the second derivative of velocity, or the third ...
uhoh's user avatar
  • 148k
7 votes
1 answer
1k views

Hubble gained weight while in space; Which components account for this extra mass?

NASA lists hubbles masses: At launch: 11,110 kg After the last service mission: 12,247kg. That's a 1137 kg increase, about 10%! Which parts are responsible for this increase ? And is there a ...
Antzi's user avatar
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13 votes
3 answers
2k views

Would it be possible for SpaceX's BFR to return the Hubble Space Telescope to Earth in the future?

Ever since the Space Shuttle retired, there was an unpopular decision to leave the Hubble Space Telescope until it eventually stopped working, since there was going to be no way to return it to Earth. ...
mjuarez's user avatar
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4 votes
2 answers
837 views

Does the Hubble telescope use a "simple" PID-controller for its pointing control system?

I am wondering whether the Hubble Space Telescope uses a "simple" PID controller like this: Or is it using another type of control system that may be much more complex?
LandonZeKepitelOfGreytBritn's user avatar
3 votes
1 answer
676 views

How do those little dish antennas sticking out of the HST track their target independent of telescope pointing?

Almost all the photos I see of the HST show the two small dish antennas at the ends of the two long, opposing booms with the "top" one pointed straight ahead at 12-o'clock, and the "bottom" one at 3-o'...
uhoh's user avatar
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18 votes
2 answers
2k views

Why is there a lid on the Hubble Space Telescope?

What is the lid on the Hubble Space Telescope for?
macco's user avatar
  • 291
7 votes
1 answer
165 views

What are the economics of upgrading versus refueling satellites?

It is sometimes suggested that fuel produced on the Moon or on asteroids could be launched more cheaply to dock with and refuel for example communication satellites in GEO to extend their operating ...
LocalFluff's user avatar
3 votes
2 answers
515 views

Space Shuttle fuel

As I know, Space Shuttle used the same amount of fuel for every mission. And used OMS for finishing orbit. Then how it is possible that, for example STS-1 which hadn't payload and was in roughly 266km*...
Đorđe Milanović's user avatar
8 votes
1 answer
549 views

Could the spherical aberration of Hubble have been solved using only software techniques?

When the Hubble space telescope was originally launched, there was a significant error in the way the main lens was ground, causing major spherical aberration. A repair mission was scheduled and the ...
costrom's user avatar
  • 1,053
12 votes
2 answers
1k views

What savings allowed James Webb telescope to be lighter than Hubble?

Wikipedia states: The telescope has an expected mass about half of Hubble Space Telescope's, but its primary mirror (a 6.5 meter diameter gold-coated beryllium reflector) will have a collecting ...
SF.'s user avatar
  • 55.1k
10 votes
1 answer
558 views

Why did the frequency of TLEs for the Hubble Space Telescope drop by a factor of 3 in 2009?

I noticed that the TLEs for the Hubble Space Telescope (HST) are posted almost twice a day. Then I looked back in time and saw that this rate varies quite a lot! The plot shows the time interval ...
uhoh's user avatar
  • 148k
5 votes
2 answers
967 views

What viewing angles does the Hubble Space Telescope use during its orbit in LEO, avoiding the Sun and Earth?

HST is in Low Earth Orbit. It can of course not look through Earth which at that low altitude covers almost half of the sky. As far as I know it is also never pointed even remotely close to the ...
LocalFluff's user avatar
1 vote
2 answers
2k views

Is the Hubble's orbit larger than that of the moon?

I have seen this picture: from "Hubble telescope Photos" and was wondering how they managed to get both the moon and the earth in the same frame for a shot (a relative position/orbit circles would ...
user2813274's user avatar