(See my other Space and Propulsion related posts) – I came across the article “Earth To Mars In 100 Days? The Power Of Nuclear Rockets” today and wanted to share it.
The idea of a nuclear rocket engine was developed in the 1960s for NASA. The research was led by Werner von Braun and successfully tested in Nevada.
What is a nuclear thermal rocket?
A conventional chemical rocket carries combustible chemicals which are ignited, then the resulting gases flow out of a nozzle propelling the vehicle. In a nuclear rocket, a small marble size chunk of Uranium fuel undergoes fission. This energy released heats hydrogen to very high temperatures (nearly 2500 C). The hydrogen is then expelled from the vehicle in a nozzle like on chemical rockets. The difference is that nuclear propulsion is two to three times as efficient. Tests were carried out starting in 1955 that have proven that this technique will work. Testing was discontinued in 1973.
Where are we Now?
The original design required highly-enriched uranium. Current designs will most likely rely on low-enriched uranium. This would make nuclear propulsion systems safer to work with. On May 22, 2019, the US Congress approved $125 million to fund new nuclear thermal propulsion development.
Another alternative being researched is using fusion instead of fission for propulsion. The Princeton Plasma Physics Laboratory is working on what they call the Direct Fusion Drive. Applied Fusion Systems is also at work on a fusion alternative.
Whether it is fission in the short term or fusion in the long term, the prospects for nuclear-powered rockets looks very positive. Read the full article for more details.
(See my other Space and Propulsion related posts) – The idea of a ‘sailing on light’ with a Solar Sail has been around for a while. A test flight of LightSail 1 (formerly LightSail-A) was launched on May 20, 2015. While the mission had problems, the LightSail 1 flight was considered a success.
The larger LinghtSail 2 is scheduled to launch June 24, 2019, aboard a SpaceX Falcon Heavy rocket.
While the preliminary tests in Germany seem to indicate that the EM Drive is impossible, DARPA, the Defense Department agency that funds technological research, has signed a $1.3 million contract for further research. This research will be part of the Nascent Light-Matter Interactions (NLM) program.
Why is DARPA investing in a propulsion technology that is generally considered impossible? In part because the test results have not yet been definitive that the EM Drive is impossible. There is also concern that a technology that the Chinese claim to have made progress with cannot be ignored.
It will be interesting to see what new announcements will appear regarding the EM Drive.
Propulsion – I have been watching the stories in the media on the EM Drive for a while now. If you are new to this, the EM Drive is a resonant cavity thruster. In simple terms, it is an electrically powered thruster that requires no fuel. It was proposed by Roger Shawyer in 2001. Most consider the EM Drive to be impossible as it defies currently known physics.
Previous tests of an EM Drive prototype by NASA showed some success. The EM Drive was subjected to more strict testing by a team at the Dresden University of Technology in Germany led by Martin Tajmar. They presented their results at the Aeronautics and Astronautics Association of France’s Space Propulsion conference on May 16, 2018. Their tests are not supportive of the claims made for the EM Drive.
The results presented by Tajmar is reviewed in the video above by Scott Manley. Tajmar and his team had not totally given up on the EM Drive at the time of their report. They plan further testing, but the prospect of this being the solution to propulsion hoped for is dim.
- ‘Impossible’ EM drive doesn’t seem to work after all
- EmDrive: Not Quite (Yet?) the Answer to Space Travel
Space – I came across the article “Here Is the Future of Interstellar Spacecraft” yesterday and thought it was a good overview of the propulsion technologies that are likely to take future spacecraft beyond the Solar System.
In short the alternatives that are covered are:
- Thermonuclear propulsion
- Bussard ramjet
- Antimatter rockets
- NASA’s Eagleworks Lab “Warp bubble” drive
None of these are really going to be ready in the near future, with possibly the exception of the Lightsail. I am glad to see though that the ideas are being kept in front of people, particularly those budding STEM students who will lead the way over the next few decades.
We have all heard of Warp or other Faster Than Light (FTL) drives in science fiction, but are they really possible?
This short (11:54) video goes into the details of the Alcubierre Drive. While so far this drive is just theoretical, there is a strong technical basis for the drive. Certainly there are several barriers to building one of these today, but there are new achievements and discoveries every day that may break down some of these.
There has been some experimental results out of NASA that tends to support some of the aspects of the Alcubierre Drive, but at this point the Alcubierre Drive is mostly theory.
I have mentioned the EmDrive several times in articles on space propulsion. The EmDrive is in the news again because a peer-reviewed paper on the drive has been submitted by NASA’s Eagleworks.
That does not mean that the EmDrive has been proven to actually work, but it does mean that it is getting some serious scientific attention. The video above is a good overview of the EmDrive by physicist Scott Manley. He talks about how the EmDrive is supposed to work, as well as the physics that says that it shouldn’t. (Manley has his own YouTube channel).
If you have interest in the EmDrive, it would be worth your time (about 16 minutes) to watch this video.
I have been a Star Trek fan since the series first debuted on TV in 1966. I came across this video and thought that it gave a good look at the ‘science’ of the Star Trek universe. It also touches upon the desire the fiction of Star Trek has instilled in many to make it possible to literally ‘go where no man has gone before’.
I look back at the 50 years that have passed since the series began and see how the series has continued to give us a look at the possible technology of the future. During that same time we have seen our real science evolve. The cell phones, tablet computers, 3D printers, and voice computer UI all had affiliated tech in the 1966 Star Trek episodes. There is even an on-going competition (the Tricorder X prize) to see who can develop a working “Tricorder” for medical
If you are interested in the Star Trek universe or in technology and the possibility of interstellar travel, this video will be of interest.
I have mentioned the EM Drive in several articles on Space Propulsion. Perhaps we will learn a little more when the “Estes Park Advanced Propulsion Workshop” is held in Estes Park, Colorado beginning tomorrow.
The conference is being held by Space Studies Institute (SSI). There will be multiple papers presented on the EM Drive or related technology. Hopefully we will learn a little more and perhaps begin to have a conclusive answer to this controversial theory on space propulsion.
I have mentioned the controversial EM Drive several times in Space Propulsion related articles. We may know soon if the drive really works once and for all. Guido Fetta of Cannae Inc has announced that they will work to launch a 6U cubesat to test the drive.
Fetta has an interest in this as he is the inventor of the Cannae Drive, which is related to the EM Drive. Both are closed microwave based systems with no conventional exhaust as the propellant.
While proving the drive does work would be a huge milestone for space travel, few in the scientific community give it much home.