Linking JWST and human spaceflight
by Michael Kaplan
|If it’s not possible to build a facility to perform JWST’s science for less than the current $8.7 billion life-cycle cost estimate, then perhaps the US needs to decide if is it going to do edge-of-the-universe astronomy or not.|
But what do we do now? As it stands now, JWST’s costs can’t be fulfilled within the budget of the Astrophysics Division. In addition, its costs have become so large so as to make it difficult for it to be implemented even within the entire Science Mission Directorate (SMD) budget without severely impacting the new mission plans for the other science disciplines within SMD. That’s not acceptable, so it’s been reported that JWST is now being thought of an “NASA priority”, meaning that it would use additional funds from other parts of NASA. The most likely contributor would be the newly formed Human Space Flight Directorate. I’ll have more to say about that in a bit.
It occurs to me that one major lesson from JWST is that it might not be possible to build a facility like JWST for less than $10 billion. JWST’s complexity, with large deployable optics and other systems operating at 40 K in an environment precluding any repair or servicing missions, has probably created one of the world’s most complex and expensive integration and test (I&T) programs. I would bet that the evolution of the JWST I&T program as the project has matured is a major contributor to its cost growth.
There’s been some talk of descoping or cancelling JWST because of these large cost increases. Recent House actions to delete JWST’s funding from the fiscal year 2012 NASA budget have exacerbated these discussions.
If it’s not possible to build a facility to perform JWST’s science for less than the current $8.7 billion life-cycle cost estimate, then perhaps the US needs to decide if is it going to do edge-of-the-universe astronomy or not. If the pursuit of these science objectives is in the national interest, then JWST needs to continue. If not, then cancel JWST, knowing that there will be scientific boundaries beyond which we simply cannot afford to explore. This latter choice I find deeply troubling.
If we look back at the enormously successful Hubble Space Telescope (HST) program, we are reminded of enormous impact that HST has had on astronomy and our understanding of the Universe. But, in fact, HST has played another very important role that is often overlooked. HST is one of the very few NASA programs that integrated the two major elements of NASA: science and human space flight. Without its ability to be serviced and accessible in low Earth orbit (LEO), HST would have been an enormous failure because it was launched with a perfectly flawed primary aperture. Once it was “repaired”, astronauts would periodically visit HST to upgrade its set of cameras as well as to replace failing subsystems.
So now here we are with NASA considering making JWST an agency priority, which probably will mean using some funds that would come from the human space flight accounts to make up some of the projected budget shortfalls to implement JWST. Is that the best that NASA can do?
Why not make JWST a “poster child”, like HST was, for how science and human space flight can synergistically make something even better?
My understanding of the current situation of human space flight of NASA is that it’s in transition from the era of the Space Shuttle to that of commercial access to LEO, with the hope of moving beyond LEO in the not-too-distant future. But where? And when?
I contend that JWST can provide answers to both of those questions.
|Why not consider making JWST telerobotically serviceable—eliminating the costly need to human-rate JWST for servicing—from a human-tended facility that could also support potential future lunar tele-robotic operations?|
There have been many recent advances in robotics and tele-robotics technologies for space applications. A few years back, the Orbital Express program successfully demonstrated fully autonomous robotic servicing of a satellite in orbit. On Earth, we are witnessing exploration of hazardous regions and even remote surgery using telerobotics. Some has been investigating the use of telerobotics for lunar exploration. One key to making effective use of telerobotics on the Moon is to require latency times of less than 400 milliseconds. To do so could require the presence of humans nearby the surface of the Moon.
Why not consider making JWST telerobotically serviceable—eliminating the costly need to human-rate JWST for servicing—from a human-tended facility that could also support potential future lunar tele-robotic operations? I presume that the current development schedule is too far along to make it possible to modify the design of JWST and its instruments to support the kind of instrument upgrades and orbital replacement units that HST used throughout its mission.
However, if a very small grapple fixture was attached to the JWST payload attach ring area, and refueling lines are made accessible, it seems reasonable that a human-tended telerobot could help support an extended lifetime, rather than the five to ten years that JWST is currently slated to operate. This extended lifetime would significant increase the science return from JWST, perhaps helping to “justify” the additional development costs. In addition, the grapple fixture might also allow mitigation for a deployment failure that a robot might be able to fix, preventing a “loss of mission” failure. It might also be possible to fly a starshade (such as proposed for the New Worlds Observer mission) with JWST and do spectroscopy of rocky planet atmospheres.
So perhaps one could modify JWST’s plans for a launch in 2020 and have its first service call in 2025. This would allow time for the construction of a small, human-tended facility to be launched.
What are the advantages of this approach?
There are downsides to this approach, including the possibility that the cost could grow even more. How much more is hard to say.
But I ask, why build a $8.7-billion disposable observatory, in the process hindering progress in human space flight, when you can build a long-life serviceable observatory that could also provide human space flight a shot in the arm when it’s most needed?