Category Archives: Space Systems

Mars voyage radiation level found in range expected – Improved shielding can deal with it

On Thursday NASA released the results of a study of radiation dosages measured on the Curiosity rover during its flight from earth to Mars.  Radiation Measured by NASA’s Curiosity on Voyage to Mars has Implications for Future Human Missions – NASA

This led to some articles with headlines like this one: NASA: Mars Travelers Would Get Fried By Radiation – Popular Science.

However, such headlines are sensationalistic over-reaction. As indicated in a report in Nature (link via Bob Zimmerman), the radiation level is about what was expected and it appears the dosage can be reduced to acceptable levels for human spaceflight to Mars by using shielding that is attainable : Spacecraft data nails down radiation risk for humans going to Mars: Improved shielding technology could keep exposure within acceptable levels – Nature

[Physicist Sheila Thibeault of NASA’s Langley Research Center] says that she is heartened by the new study because she had feared that the radiation dose might be considerably higher. The results suggest “that this is a problem we can solve”, she adds.

As indicated in the Nature article, hydrogenated shielding is ideal. Besides the new materials discussed, the habitat for a Mars crew can be designed in a manner that surrounds the living areas with the water, food, waste,and fuel that they will be carrying anyway. This will add up to significant amount of hydrogenated shielding.

I’ll also note that the worst case dosage, “0.66 sieverts of radiation during the voyage to and from the planet”, would increase the crew’s chance of cancer by 3 to 4 per cent. This is consistent with what the Inspiration Mars project has said that they were expecting to deal with. It appears now that they can improve on this since they are planning to use the above shielding techniques with water, food, etc.

X-37B update

Leonard David gives the latest on the X-37B currently in orbit: US Military Space Plane’s Mystery Mission Passes 5-Month Mark –

The U.S. Air Force’s robotic X-37B space plane has quietly passed the five-month mark on its latest secret mission in Earth orbit.

The unmanned X-37B spacecraft launched into space atop an Atlas 5 rocket from Florida’s Cape Canaveral Air Force Station on Dec. 11, 2012, kicking off a mission whose objectives and payloads are classified.

Here’s a video of the launch:

Sunjammer solar sail to fly far in 2014

The NASA funded Sunjammer Project will fly the largest solar sail ever deployed in space, a  1200 sq. meter sail built by L’Garde. Scheduled for launch on a SpaceX Falcon 9 rocket in 2014, the Sunjammer spacecraft will aim for a location 300M kilometers from earth. The goals of the project include:

1. Demonstrate segmented deployment of a solar sail with ~4X the area of that vacuum tested at Plum Brook, “cookie cut” from the center of a much larger sail.

2. Demonstrate attitude control plus passive stability and trim using beam-tip vanes.

3. Execute a navigation sequence with mission-capable accuracy.

4. Fly to and Maintain Position at L1 and pole sitter positions

Taking advantage of the sunlight force on the sail, such spacecraft should be able to achieve stable orbital locations relative to earth that would provide excellent places to detect solar  storms and send warnings back home. Sunjammer will carry two solar wind measurement  instruments built by groups in the UK: