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Hope for Hubble
yulek writes "It may not be over yet. space today reports that Bush's NASA administrator nominee, Michael Griffin, wants to revisit the Hubble decision. Space.com has some more details.
The big question is: do we really want to save Hubble for the right reasons or is it more of a symbolic thing? Considering NASA's fiscal woes, is this a waste of funds?
I have loved the Hubble images for the last decade, and the research that stemmed from them, but I think that the most incredible camera we've ever made may need more than just an upgrade. Perhaps it is obsolete."
I generally consider things to be obsolete when they have been replaced by something better. How does this apply to Hubble?
samrolken
If you have a copy of the Hubble Manual, 24 April 1990, NASA will pay you $10,000.
A feeling of having made the same mistake before: Deja Foobar
Considering how low it takes to get a probe beyond Pluto and the strange pull on the spacecraft (it is off where it should be) and the low cost of continuing to monitor the probes, the voyeger missions should be continued too. Cutting them saves very little money but the budget is so tight that to save one or two mil, we are cutting these very important programs.
"Those that start by burning books, will end by burning men."
If you don't have $400M to fix a space telescope, you're not going to get $4B+ to build a new one.
Consider, further, that if a hypothetical new telescope has a $400M sticker on it today, it'll cost at least $4B by the time Congress is done splitting up the contracts so as to maximize the amount of pork (and therefore votes) allocated.
Consider, still further, the probability that this (or any other) administration is ever going to agree to spending one thin time on science. People into science tend to think. People who think tend not to vote as predictably. It's therefore in every Congressman's long-term interest to reduce the proportion of such people among the population.
This isn't an R-vs-D flame. Space telescopes harm Republican politicians by draining money away from faith-based initiatives that would otherwise be used to indoctrinate the next generation of Republican voters, but they also harm Democrat politicians by draining money away from social programmes that foster the kind of nanny-state dependency that produces the next generation of Democrat voters.
I support keeping the Hubble - even if obsolescent, it's better than nothing. And "nothing" is what we'll end up with if we let it crash and burn.
As prior art, I cite the X-33 and other Shuttle replacements, all of which were canned years ago.
This sounds just like the Terri Schiavo case, except set in space!
As for ground-based telescopes, any space-based instrument has access to the continuous range of wavelengths, whereas ground-based telescopes (even with adaptive optics) are limited by the absorption and scattering in the atmosphere in the UV and infrared. They also don't have to deal with sky glow, which restricts both how long you can take an exposure for -- eventually the background will saturate your detector -- and also the contrast between the thing you're trying to detect and the background (think picking out a small light on a white background against on a dark background).
This is also why Earth-based telescopes are put on mountains -- to get above as much of the atmosphere as possible. Adaptive optics can improve the "seeing" (blurring caused by turbulence) and, coupled with large-diameter mirrors possible on ground-based telescopes, it will improve the resolution, but it can't deal with the other effects,
Because there gyroscopes. The Reaction wheels provide the energy to change HST's orientation and the gyros provide the feedback to sense the movement. Hubble's pointing and control systems are more fascinating to me than the science instruments.
And where did you hear that it would cost less to build another?? Last I heard, only $300,000,000 or so is allocated for the SM. I'd like to see you build a telescope with the same stability and accuracy as HST for that little.
Stop the use of force!
Found it! Its called the Hubble Origins Probe http://www.pha.jhu.edu/hop/ The Hubble Origins Probe (HOP) is a proposed 2.4 meter free flying space telescope.The HOP concept is to replicate the design of the Hubble Space Telescope with a much lighter unaberrated mirror and optical telescope assembly, enabling a rapid path to launch, significant cost savings and risk mitigation. HOP will fly the instruments originally planned for the 4th HST servicing mission as well as a new very wide field imager, enhancing the original science mission of Hubble.
As someone working on the Hubble robotic servicing mission (I know most /.ers will say this biases my opinion; really it just means I can speak from a position of knowledge), I can state 100% that this mission can be done, and can be done on schedule.
Let me break down the phases of the mission for those who are unaware:
1.) Launch - needs little explanation - a Delta IV or Atlas V heavy lift launches the HRV into Hubble's orbital plane
2.) Checkout & Commissioning - The robot arm and other HRV elements are tested and verified operational
3.) Orbit Phasing & Rendezvous - The craft will be commanded to approach Hubble. Autonomous systems will be used to coordinate the final stages of this approach, using technologies currently being proven out on the XSS-11 spacecraft which launched this week, and to be launched next week on the DART spacecraft.
4.) Capture & Berthing- The robot arm is set up for capture, and when the vision system determines that the end effector is within tolerances, an autonomous capture is performed. HRV is performing station-keeping until just before, and when HRV and HST are known to have a negative relative drift rate (receding), the capture process is allowed to begin. A capture ends with the arm grappled to one of HST's shuttle grapple fixtures. The vision system is in development, and the hardware has been space-proven for the past ~20 years on Shuttle... in fact the exact same end-effector design has been used on all previous HST servicing missions. After Capture, the arm decelerates HST and then engages it into the HRV latches (same latching arrangement as on a shuttle servicing mission).
5.) Battery Augmentation - HST's batteries will die soon, and are one of the prime schedule drivers for the mission. The dexterous robot (two armed robot) connects wire conduits from the HRV batteries to the outside of HST and routes solar array power to them. The hardest part of this task is transfering the 2 prime or 2 redundant connectors on each of the port and starboard diode boxes (located just under the solar array masts). This operation has been proven out on the ground, using a validated flightlike 1G testbed version of the actual dexterous robot, and a hi-fi Hubble mockup. In fact I think operators demo'd this very op just yesterday for maybe the 20th time. Trust me... it's highly doable.
6.) Changout WideField and add Gyros - The gyroscopes are the next most likely item to fail on HST, and are another schedule driver. With the new two-gyro mode currently under investigation, the lifetime of HST could likely be extended beyond the 2007 timeframe. The Rate-Gyro Assemblies are attached conveniently to the outside of WFC3, the replacement wide-field camera for WFPC2. WFPC2 is the camera responsible for most of the majestic galaxy and planetary photographs we seen in the news and magazines. WFC3 will improve yet again over that. Changing out WFPC2 involves de-mating the internal connectors, removing the ground-strap, unlatching the instrument, and sliding it out of the -V3 radial instrument bay rails. The old instrument is transported down to a stowage location in the HRV, and the new instrument is installed in the empty HST bay in the reverse sequence. This entire operation has been demo'd several times over the past year.
7.) Changeout COSTAR - After the two critical repairs (batteries and gyros), we move into the get-aheads and upgrades. The COSTAR instrument, sitting in axial bay 4, has performed corrective optics functions since its installation during the first servicing mission. Now that all HST instruments are built with integrated corrective optics, this instrument is obsolete, and can be replaced by something more productive; the Cosmic Origins Spectrograph (COS). To perform the changeout, the robot must unlatch and open the -V2 aft shroud doors, attach a handling fixture to COSTAR, attach a connector transfer panel to the handling fixture, transfer the 4 COSTAR harness connectors, transfer the ground