Tag Archives: Space

Rosetta Lander to Attempt Comet Landing

The lander from the ESA’s Rosetta probe is scheduled to attempt to land on the 67P/Churyumov-Gerasimenko comet early Wednesday morning. The probe has been orbiting and studying the comet for the past few months. The lander is designed to study various properties of the comet, such as its chemistry. Landing on a comet is a challenging process since operators will have very little control over what happens. The Times article mentions that the Rosetta mission is very important since it will be the first mission to study a comet over a long period of time.


Virgin Galactic Test Craft Crashes

It’s been all over the news since yesterday that one of Virgin Galactic’s test planes, SpaceShipTwo crashed yesterday, killing one pilot and severely injuring another. In addition to the human toll of this accident, it will also be a serious setback to the development of commercial space transportation. A full investigation into what happened and why should lead to improvements in the safety of these prototype spacecraft. Any serious accident is a major problem for commercial spaceflight, so this may very well set back any potential commercial operations by years. If anyone hopes to operate commercial spaceflights, the technology needs to be extremely safe. Hopefully, Richard Branson is truly interested in building a viable company based on viable, reliable technology and not just a vanity project to get himself and his friends to space.

Partial Solar Eclipse Tomorrow

Just in case you haven’t heard, there will be a partial solar eclipse tomorrow (October 23rd) across much of North America. NASA has the details so you can see when the eclipse will be most visible where you are. Unfortunately, it looks like it will be strongest around Nunavut. As always with solar eclipses, be very careful viewing it. You don’t want to damage your eyes. Since this is a partial eclipse, it’ll probably be hard to look directly at the sun unaided anyway.

New AMS Dark Matter Results

PRL published a couple new papers from AMS today, including this one, which shows an updated plot of the positron fraction (e+/(e+ + e-)) as a function of energy. I don’t think these have been posted to the arXiv yet, which is unusual for our field. Unfortunately, PRL must be accessed either through a network with access or with an account, which requires money, so if you’re not at a university and aren’t an APS member you might have trouble looking at the paper. In conjunction with the papers being released, there was a seminar at CERN earlier today. I didn’t find out about the seminar until it was too late for me to try to call in remotely.

AMS is a large multipurpose detector based at the International Space Station that studies cosmic rays, which are high energy particles flying around in space. The search for dark matter is one of the main purposes of the experiment, but it can study many things about cosmic rays, such as their composition, energy spectra, directions, etc.

This paper shows the positron fraction up to 500 GeV, which is a bit higher than in previous measurements. This measurement is useful for looking for dark matter annihilation to electron-positron pairs. The expected signal is for the positron fraction to increase at some energy and then peak and drop fairly sharply at an energy of approximately the dark matter mass. Previous measurements from AMS, Fermi, PAMELA and ATIC have all seen an increase in the ratio and have even seen the spectrum seem to level off. This new measurement shows that the leveling off continues, and the spectrum may even be starting to fall in the highest energy bin. However, the measurement is limited by both statistics and systematics at the highest energies, so the apparent decrease in the highest bin is not going to be statistically significant at this point in time. That may change with more events in the future and hopefully a better understanding of the detector and of astrophysical models for the non-dark matter background.

NASA Announces Manned Spaceflight Contracts

Earlier today, NASA announced the winners of contracts for developing spacecraft to send astronauts to the Interantional Space Station. Both Boeing and SpaceX have been awarded contracts, with Boeing receiving $4.2 billion and SpaceX getting $2.6 billion.

I would guess that Boeing received the most because it has a long track record of supplying equipment to the US government. NASA can safely assume that Boeing is capable of completing the contract. SpaceX hopes to be able to do spaceflight cheaper than anyone else but also hasn’t previously been involved in such a major undertaking. The contract shows that NASA is confident that SpaceX can do it, but they also won’t want to risk the whole program by awarding all the money to a company that hasn’t shown itself to be reliable.

Having two options is also a good idea so that a delay in one of them doesn’t necessarily delay the return of NASA-led manned launches. It might also turn out that the two vehicles are better at different things, so maybe some missions will favor Boeing and some SpaceX. Having some competition might also keep costs down.

NASA hopes to have the first launches in 2017, so we’ll still have a couple more years without having manned launch capabilities. Many had criticized the US government for ending the shuttle program because of this gap with no manned launch vehicle. The shuttle was a decades-old design that was very expensive and very risky for the crew, so I think that discontinuing shuttle launches was probably the right move. We should have already had a replacement vehicle ready, but not having one is not a sufficient justification to continue risking astronauts’ lives when safer but not US-led options were available.

Salon on Extraterrestrial Intelligent Life

Salon has an interesting article reposted from Scientific American on whether or not we’ll ever find intelligent extraterrestrial life. It actually gives what seems like a reasonable argument, which is surprising given the amount of pseudoscience attached to anything involving aliens.

Unfortunately, the author’s view is not very satisfying. A few decades from now it’s likely that we won’t know any more than we do now. We can now find other planets, but even if they have intelligent life there’s no guarantee that we’ll ever find it. We don’t even have a good way to estimate how likely it is that such life exists or whether we’ll find it assuming it exists at all. Whether or not intelligent life outside Earth exists will probably remain a philosophical question for the foreseeable future.