How Much Longer Will the Hubble Space Telescope Last?

How Much Longer Will the Hubble Space Telescope Last?
1 Oct 2019

https://blogs.discovermagazine.com/d-brief/2019/10/01/how-long-will-hubble-telescope-last/

...the telescope’s instruments are likely to last longer than to 2030, although it has not been without its hiccups — the most recent of which affected Hubble’s Wide Field Camera 3... On January 8, 2019 the telescope’s camera abruptly stopped working when it detected voltage levels outside of the expected range. That set engineers searching for what caused the problem. After investigating the issue, the team found that the voltage levels inside the camera were actually normal. Instead, data in the instrument’s telemetry circuits wasn’t accurate. ...many of the older instruments are not operating at full capacity. Certain parts of their detectors no longer function or must be carefully masked using software to ensure the data they take are accurate. Even with these limitations, however, the telescope is still an invaluable asset for science.

Hubble’s Wide Field Camera 3, which was installed in 2009 when the telescope was last serviced, has taken more than 240,000 observations to date, contributed data to over 2,000 peer-reviewed published papers, and is the most-used instrument aboard the orbiting space telescope.

Almost 29 years since Hubble was launched, the Hubble Space Telescope is still a workhorse for exploring the universe. It provides a glimpse at some of the cosmos’ most incredible objects. Still, with its age, the telescope has faced a number of recent technical obstacles.

In October, Hubble’s science observations stopped for three weeks when one of its gyroscopes failed. The gyroscopes control how the telescope points and orients itself, and this failure left the telescope with only three of its six gyroscopes operational. Three weeks after the failure, Hubble resumed operations with these three gyroscopes. Thankfully, the remaining gyroscopes are expected to last longer than the gyroscopes that have already failed.

Winston said:

Thankfully, the remaining gyroscopes are expected to last longer than the gyroscopes that have already failed.

Click to expand...

That's actually pretty funny because *technically* the remaining gyroscopes have already lasted longer than the ones that failed. Right?

That's good. The Web telescope, if it ever arrives, will only see in the infrared. The Hubble can complement other telescopes in the visual range.

The Hubble orbits at about 350 miles while the ISS is at 250 miles. For some reason I've always thought the Hubble was much further out. I know it's at that height because that's the limit of how high a Shuttle could get to with it. Geostationary orbit is about 22,200 miles.

The article said, "HST will eventually experience enough atmospheric drag that it will crash to Earth; this is projected to occur by the mid-2030s" which made me wonder just how low it was orbiting so I looked up all that info above just now. That is surprising that something that high will fall from orbit that soon. I wonder how long it would take the geostationary satellites to come down due to drag?

A very long time

https://www.spaceacademy.net.au/watch/debris/orblife.htm

Mushtang said:

That is surprising that something that high will fall from orbit that soon.

Click to expand...

It is very light for its exposed area, including the solar panels. 43 feet long, about 12 feet or so diameter plus BIG panels. More like a wiffle ball than a baseball. A say 6 foot sphere of the same mass would stay up a LOT longer (more like a lead ball than a baseball).

Peartree said:

That's actually pretty funny because *technically* the remaining gyroscopes have already lasted longer than the ones that failed. Right?

Click to expand...

I was thinking that some of the gyros may have been replaced on a service mission and, therefore, had not been operational as long as the ones that failed, but I just checked and ALL six gyros were replaced on the last servicing mission in 2009. So, you are correct.

SO, the next question that would come to mind to anyone other than idiot journalism majors playing Frisbee in the dorm hallways and disturbing the engineering students studying would be, "WHY do you expect them to last longer?" Were they off-line as backups and have fewer hours on them? By lasting longer do you mean longer overall lifespan while in operation and, if so, what leads you think that will be so? No, I'm not going to do their job and research this... for a change.

IIRC the bearings in the earlier gyros had steel balls. Static electricity was causing pitting as it discharged through the balls and race as the bearings rotated. Eventually the bearings were too mechanically noisy and experienced too much friction.

The later bearings had ceramic balls and earth connections on the central shaft to dissipate the charge buildup.

aerostadt said:

That's good. The Web telescope, if it ever arrives, will only see in the infrared. The Hubble can complement other telescopes in the visual range.

Click to expand...

Webb is tuned for distance. The NIRCam has a similar wavelength range to Hubble's WFC3 scaled for a redshift of 2. (20 giga light years / 11 billion years ago) The MIRI instrument scales to z ~ 20 - looking for the first stars at 40 GLY / 13 billion years.

I was about to say that redshift is weird - but the whole frackin' Universe is weirder.

Since the Web telescope is tuned for the infra-red it can catch the spectrum that is not attenuated by all the dust spread throughout interstellar space.

OverTheTop said:

IIRC the bearings in the earlier gyros had steel balls. Static electricity was causing pitting as it discharged through the balls and race as the bearings rotated. Eventually the bearings were too mechanically noisy and experienced too much friction.

The later bearings had ceramic balls and earth connections on the central shaft to dissipate the charge buildup.

Click to expand...

Yes, I recall reading that, too, and I may have even posted something about that here although I think it may have been related to reaction wheels and their high failure rates. Anyway, regardless of that, all Hubble gyros were replaced at the same time, so the question remains about why NASA thinks the ones still working will last longer in operation than the ones that have failed. Perhaps some health monitoring sensors on the gyros tell them this?

Unfortunately, we no longe have the shuttle to work on it. I think when it is EOL it will be space garbage.

cwbullet said:

Unfortunately, we no longe have the shuttle to work on it. I think when it is EOL it will be space garbage.

Click to expand...

If we do what we should have started doing long ago since the tech isn't terribly advanced, and start using telepresence robotics mounted on reusable, unmanned spacecraft which can carry cargo (think X37B, I suspect...) controlled by humans on the ground to service satellites DESIGNED to be serviced in that manner, maintenance of high value satellites (like Hubble... or the "Hubbles" looking downward) in low Earth orbit (to reduce control delay) will be possible. Both NASA and DARPA are working on robotic servicing. I've previously posted stuff about that here. Here's an upcoming launch of a simpler kind of servicing in that it doesn't replace internal satellite modules, it's just an add-on propulsion package.:

Satellite industry’s first robotic servicing mission ready for launch
8 Oct 2019

https://spaceflightnow.com/2019/10/...t-robotic-servicing-mission-ready-for-launch/

A pioneering Northrop Grumman-built satellite designed to dock with an aging spacecraft more than 22,000 miles above Earth, then extend its life with the aid of solar-electric thrusters, is set for launch Wednesday from Kazakhstan aboard a Proton rocket.

The first Mission Extension Vehicle, or MEV 1, will link up with an 18-year-old Intelsat communications satellite early next year. Once docked, the MEV 1 spacecraft will take over propulsion for the Intelsat 901 satellite, which is running low on fuel.

MEV 1 is the industry’s first commercial servicing mission, and will attempt the first-ever docking between two spacecraft near geostationary orbit, a region more than 22,000 miles (nearly 36,000 kilometers) over the equator that is popular with communications satellite operators.

“Once Proton gets us to the to the transfer orbit, they will first deploy the Eutelsat satellite, about 20 minutes later, they’ll deploy the MEV,” said Joe Anderson, vice president of business development and operations at Space Logistics. “And then the MEV will begin its orbit-raising mission. That orbit-raising mission will take us about three to three-and-a-half months to get out to the rendezvous orbit. It takes that long primarily because we’re using mostly electric propulsion to do our orbit-raising.”

Artist’s illustration of the Intelsat 901 satellite (left) after the docking of the Mission Extension Vehicle (right). Credit: Northrop Grumman

I'm just gonna give 'er the industry standard. Which just so happens to be 2 weeks.

Mushtang said:

The Hubble orbits at about 350 miles while the ISS is at 250 miles. For some reason I've always thought the Hubble was much further out. I know it's at that height because that's the limit of how high a Shuttle could get to with it. Geostationary orbit is about 22,200 miles.

The article said, "HST will eventually experience enough atmospheric drag that it will crash to Earth; this is projected to occur by the mid-2030s" which made me wonder just how low it was orbiting so I looked up all that info above just now. That is surprising that something that high will fall from orbit that soon. I wonder how long it would take the geostationary satellites to come down due to drag?

Click to expand...

The HST orbit degradation is not going to take place overnight.

As the HST orbit degrades over time it will eventually come down into a lower orbit within the range of manned space vehicles and additional servicing missions should be possible in theory-- whether they'd be cost-effective would be a whole other question of course.

At least in theory when the HST orbit degrades into something more comparable to the ISS, a servicing mission could be sent to renovate/replace failing components, then attach a booster unit to boost it back up into its higher operating orbit (and presumably give it another 40 years of existence.)

If it was determined the HST was operationally obsolete and unsalvageable, the same booster unit could be used as a retrofire unit to
direct reentry to suitable uninhabited areas, rather than a Skylab-style uncontrolled random reentry.

A Hubble retrieval/ repair mission could certainly be done as part of any beyond-LEO space program in the next several decades, whether it's a lunar base, an asteroid mission, or a trip to Mars.

Pretty much any or all of those would require in-orbit rendezvous and repair-task capabilities.