Trump space advisors considering Hubble servicing mission
The Wall Street Journal reports that Trump administration advisers 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.
Requirements to make the mission a reality
The Wall Street Journal suggested the mission would align well with the Trump administration’s desire to advance public-private partnerships while also advancing missions that could be accomplished within the president’s current four-year term.
According to the Wall Street Journal story, Mark Sirangelo, head of SNC’s 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 Wall Street Journal story also stated that updating Hubble would require relatively few additional dollars because the telescope has a modular design and Dream Chaser’s 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.
Previous repair efforts
Having launched aboard the Space Shuttle Discovery on STS-31 in 1990, Hubble’s 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 telescope’s science mission.
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 NASA’s Goddard Space Flight Center, told CBS News in 2013 that he believed Hubble could operate up to 2020.
Without a reboost, Hubble will re-enter Earth’s atmosphere sometime between 2030 and 2040.
Is it worth it?
Dream Chaser’s availability aside, the question remains: Is a sixth mission to Hubble a good investment of NASA’s 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. It’s 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. It’s not clear to me whether or not a Dragon or Starliner could carry out the same sort of mission. The SNC’s cargo variant’s expendable mission module could make for a great airlock to allow [a] crew to egress. But none of these vehicles have an arm for grappling Hubble […] so you’d have to do some interesting EVA work to tether them together.”
When asked if Hubble’s 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. Regarding the potential worth of a Hubble servicing mission. Dr. Illingworth told Spaceflight Insider:
“The question of the ‘worth’ of another servicing mission hinges on a careful evaluation of the capabilities of the upcoming WFIRST [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 [on] 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 serviceable—and maybe even will be assembled and tested in space by astronauts and robotic capability.”
Why not service JWST?
The James Webb Space Telescope (JWST), Hubble’s 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, JWST is not designed to be serviced in space. Lynn Chandler with NASA’s 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.”
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.