Bart Leahy

February 16th, 2017

The Hubble Space Telescope as seen by the departing STS-125 crew after a week servicing the observatory in 2009. Photo Credit: NASA

The Wall Street Journal reports that Trump administrationadvisers are considering a public-private crewed mission aboard the Sierra Nevada Corporation (SNC)Dream Chaser spacecraft to keep the aging Hubble Space Telescope (HST) operational. The proposed mission, which would not happen before 2019, would require support from the next NASA administrator.

The crew variant of Dream Chaser. Image Credit: Sierra Nevada Corporation

The Journal suggested the mission would align well with the Trump administrations desire to advance public-private partnerships while also advancingmissions that could be accomplished within the presidents current four-year term.

According to the Journal story, Mark Sirangelo, head of SNCs space systems unit, told a conference last week that Dream Chaser could be used as an exploration vehicle, a free-flight science laboratory and a servicing vehicle for in-orbit satellites and spacecraft. Additionally, an SNC representative stated that Dream Chaser was designed from the beginning to be a multi-mission orbital transportation system eventually targeting servicing, repair and assembly of technology in space.

The Journal story also stated that updatingHubblewould require relatively few additional dollars because the telescope has a modular design and Dream Chasers cargo variant already is undergoing flight tests. The vehicle would need additional life-support systems as well as a launch abort system designed to protect the crew in the event of an explosion or serious problem on the pad or during early phases of its ascent.

However, before Dream Chaser can be sent to chase Hubble in its 335-mile (539-kilometer) orbit, it first has to fly into space.

SNC is still conducting development and testing activities on the spacecraft at NASA Armstrong Flight Research Center in California as part of its Commercial Resupply Services contract. Another glide test of the vehicle is scheduled for spring 2017, with the first cargo launch to the International Space Station scheduled for sometime in 2019.

Having launched aboard the Space Shuttle Discovery on STS-31 in 1990, Hubbles primary mirror was discovered to have improperly manufactured optics, requiring its first servicing mission. That mission,STS-61, launched aboard Shuttle Endeavor in 1993. It corrected the optics and installed additional instruments to support the telescopes science mission.

Hubble Space Telescope being lifted from the payload bay of Atlantis following repairs during STS-125. Photo Credit: NASA

Four subsequent missions in 1997, 1999, 2002, and 2009 replaced items such as spectrographs, thermal insulation, gyroscopes, batteries, computers, and other components.

With these repairs, James Jeletic, deputy project manager of Hubble operations at NASAs Goddard Space Flight Center, told CBS News in 2013 that he believed Hubble could operate up to 2020.

Without a reboost, Hubblewill re-enter Earths atmosphere sometime between 2030 and 2040.

Dream Chasers availability aside, the question remains: Is a sixth mission to Hubble a good investment of NASAs time and limited budget?

Jim Muncy, a long-time space lobbyist with PoliSpace and senior adviser to the Commercial Spaceflight Federation, told Spaceflight Insider:

I think the concept of using a commercial crewed vehicle to service Hubble makes a lot of sense. Its good to see SNC thinking creatively they have always talked about DreamChaser as a platform as well as a crew/cargo transporter, so this makes sense. Its not clear to me whether or not a Dragon or Starliner could carry out the same sort of mission.The SNCs cargo variants expendable mission module could make for a great airlock to allow crew to egress.But none of these vehicles have an arm for grappling Hubble [] so youd have to do some interesting EVA work to tether them together.

When asked if Hubbles role could be supplemented by existing ground-based telescopes, Dr. Tom Brown, Mission Head of the Hubble Space Telescope, told Spaceflight Insider:

Hubble is currently performing well, and it provides unique capabilities that are not achievable from any ground facility in existence or planned (e.g., ultraviolet imaging and spectroscopy, high-resolution optical imaging with low backgrounds).We expect Hubble to provide these capabilities for at least a few years of overlap with the upcoming mission of the James Webb Space Telescope, launching in late 2018. Beyond that, the Space Telescope Science Institute has no official position regarding the servicing of Hubble to extend its lifetime.

Dr. Garth Illingworth, an astronomer at the Lick Observatory, has used Hubble to study the formation of galaxies. Regardingthe potential worth of a Hubble servicing mission. Dr. Illingworthtold Spaceflight Insider:

The question of the worth of another servicing mission hinges on a careful evaluation of the capabilities of the upcomingWFIRST[Wide Field Infrared Survey Telescope] Hubble-like telescope (similar in size) and on what we would do differently with Hubble. I have heard some interesting ideas for instruments that would be great to have on Hubble. While I might love to have Hubble serviced again, one needs a hard-nosed evaluation of the science that would be gained to decide if it is worth the cost.

What we would try to do in space for astrophysics depends a lot of what is judged to lead to the most interesting scientific results. This is always a topic of much discussion among scientists. And ultimately we look to the Decadal Survey to establish our priorities.

While JWST is not serviceable, we expect that most future telescopes will be potentially serviceable. Current plans are to make WFIRST serviceable []. And larger future telescopes beyond will surely be serviceableand maybe even will be assembled and tested in space by astronauts and robotic capability.

The James WebbSpace Telescope (JWST), Hubbles designated successor observatory, is scheduled to launch to the Earth-Sun L2 Lagrange point aboard an Ariane 5 rocket in 2018. One argument for updating Hubble is that could serve as a backup space telescope in case JWST suffers a failure of some kind.

As Illingworth noted, unlike Hubble, JWSTis not designed to be serviced in space.Lynn Chandler with NASAs JWST Communications group told Spaceflight Insider,

In the early days of the Webb project, studies were conducted to evaluate the benefits, practicality and cost of servicing Webb either by human space flight, by robotic missions, or by some combination such as retrieval to low-Earth orbit. Those studies concluded that the potential benefits of servicing do not offset the increases in mission complexity, mass and cost that would be required to make Webb serviceable, or to conduct the servicing mission itself.

Whether NASA decides to pursue this commercial Hubble servicing mission will be up to the next agency administrator. As with any new presidential administration, the answer, for now, is wait and see.

Tagged: Dream Chaser Hubble Space Telescope James Webb Space Telescope Lead Stories NASA Sierra Nevada Corporation

Bart Leahy is a freelance technical writer living in Orlando, Florida. Leahy's diverse career has included work for The Walt Disney Company, NASA, the Department of Defense, Nissan, a number of commercial space companies, small businesses, nonprofits, as well as the Science Cheerleaders.

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Trump space advisors considering Hubble servicing mission - SpaceFlight Insider