There are plenty of problems that spacecraft designers have to consider. Getting smacked in the sensitive parts by a rock is just one of them, but it is a very important one. A micrometeoroid hitting the wrong part of the spacecraft could jeopardize an entire mission, and the years of work it took to get to the point where the mission was actually in space in the first place. But even if the engineers who design spacecraft know about this risk, how is it best to avoid them? A new programming library from research at NASA could help.
Admittedly, engineers already have a tool for this purpose. NASA’s Meteoroid Engineering Model (MEM) allows them to plug in a planned trajectory for their spacecraft and receive an output that defines where and from which direction they are likely to encounter micrometeoroids.
The James Webb Space Telescope is a perfect example of why such a system is necessary. On its way to the L2 Lagrange point, it has already suffered at least 20 micrometeoroid impacts, at least one of which hit the space telescope’s primary mirror, leaving a dent that still affects the quality of its images to this day.
How do micrometeroids affect spacecraft?Credit – Chris Pattison YouTube Channel
Due to such high-profile occurrences, spacecraft designers are already aware of the risks. However, many don’t know their trajectories when designing their systems. Without a planned trajectory, the MEM is all but useless.
Enter Althea Moorhead from NASA’s Meteoroid Environment Office at Marshall Space Flight Center and her colleagues Katie Milbrandt from Auburn and Aaron Kingery from ERC, Inc., also based at Marshall. They improved the MEM’s functionality by introducing a library of known spacecraft trajectories and the MEM outputs for each.
Instead of knowing their end trajectory, spacecraft designers would be able to simply look at the library and determine whether there are any significant risks from meteoroids on any number of potential trajectories. In particular, the library includes data on orbital paths around every significant planet, some transfer orbits, and at least two “halo” orbits, where the spacecraft would take advantage of the relative stability of a planet’s Lagrange points.
How Webb deals with the micrometeroid impacts its already suffere.Credit – Launch Pad Astronomy
The output of the library allows for visualizations of the risks the spacecraft would encounter, which is much easier to understand than complex equations and probabilities for designers who don’t necessarily specialize in micrometeoroid hazards. That was the original impetus for developing the library – to provide generalists who don’t necessarily have time to grok the details of micrometeoroid location and risks but still need to consider it as part of their mission design.
The paper authors stress that the library shouldn’t be used for the formal risk assessment that NASA requires of all missions destined for launch. That requirement can still be met by the MEM itself, along with a well-established orbit. But, if that orbit happens to be informed by the library described in the paper, all the better for it.
Learn More:
Moorhead, Milbrandt, & Kingery – A library of meteoroid environments encountered by spacecraft in the inner solar system
UT – NASA has a Plan to Minimize Future Micrometeoroid Impacts on JWST
UT – What Does Micrometeoroid Damage do to Gossamer Structures Like Webb’s Sunshield?
UT – Ouch. Canadarm2 Took a Direct Hit From a Micrometeorite
Lead Image:
Visualization of one of the trajectories planned out in the new micrometeroid library.
Credit – Moorhead, Milbrandt, & Kingery
