The next, and the major, milestone for the mission is to find interference fringes. This is critical to operating the spacecraft as part of a high-resolution telescope.
Interference fringes arise from the wave nature of light. When superimposed, two wave trains cancel or reinforce. Beats between two very close notes, in music, is an example of this: where the waves are in phase they produce a strong note, and when out of phase they produce silence. For light, when two wave trains of the same frequency traveling in slightly different directions meet at a screen, they produce alternating bands of bright and dark, where the waves are in phase and out of phase, respectively. Those bands might look like the fringe on the edge of a piece of fabric -- so they are called "fringes".
Light -- and many other waves such as ocean waves -- always take the fastest path. Transparent, refracting materials such as glass slow light down. Light will bend, so as to spend less time in the slower material: even though the overall path has greater length, travel time is less. It's kind of like flying from Los Angeles to Washington DC, and then driving to Gaithersburg MD: even though you retrace part of the your path, it's far faster than driving the direct route all the way!
Interference is responsible for the ability of a lens to focus light. Refraction by the glass of the lens bends the light, so that waves from all points over the surface of the lens reinforce at the focus, and cancel elsewhere. In effect, the lens acts as a circular analog computer to form the image. Lenses are very cool in this way.
Radio waves can easily be recorded and played back using video recorders -- so the process of aligning the phases along different paths can be done by recording signals at different points, then playing them back so that they combine with exactly the correct lag. This used to be done by aligning video tapes with exactly the right offset. Nowadays, it's done by reading the data streams from the hard disk of a computer with exactly the right lag, as in a solid-state DVR.
The trick is to find exactly the right lag. That requires knowledge of the exact positions of all the radio telescopes used for the experiment. That requires knowledge of their positions to a fraction of a radio wavelength: a few cm. Or, you can perform a search of all possible positions, look for the appearance of interference, and then know the positions to that accuracy. This allows the measurement of distances between radio telescopes to a few cm, and demonstration that the continents are still drifting today. GPS works via a closely related principle: but instead of one source and many radio telescopes, it has many sources (the GPS satellites) and one (tiny) radio telescope inside the receiver.
Finding the exact position of the Radioastron satellite will be harder. Space is big and Radioastron moves fast. Various techniques are being used to track the satellite, including optical telescopes, radio delay-Doppler ranging, and laser ranging; but the test will be to find that first interference fringe on some astrophysical source. Then the scientific work can begin.
Here is my place of work in Moscow, near the Kaluzhskaya subway station. This building houses the Astro Space Center, as well as some other labs and offices. It was originally built to house chemistry research, and every other floor is a "technical floor", designed to house chemistry labs, with the narrow windows; the intermediate floors are "office floors", with the higher windows. The two categories are numbered separately, making navigation confusing.The window of the office where I work is on the uppermost office floor about halfway along the building.
Last night the international scientists attending the launch had dinner with Vladimir Popovkin, Deputy Defense Minister and the Director General of the Russian Space Agency. He is the top official in charge of all Russian space programs, manned and unmanned, civilian and military. He's attending to his work here at Baikonur, and very kindly took the opportunity of our presence to invite us to dinner. Also attending were the Director of the Lavochkin Association, and Academician Nikolai Kardashev, the Director of the Astro Space Institute of the Lebedeev Institute of the Russian Academy of Sciences.
I found Director General Popovkin to be unusually thoughtful and engaged. He started the dinner by observing that he had many chances to talk with Russian scientists about future directions for their space program, and he was very curious to hear our opinions, as visitors from overseas, as to the best directions for future Russian scientific missions, and the properties of Russia that made those the best. Our answers took the form of toasts, as is traditional at Russian dinners. He listened to our responses, and his toasts, in turn, indicated that he'd thought carefully about them.
My own toast included the observation that Russia has a long tradition of strength in theoretical physics. I ascribe this, in part, to their excellent educational system. I suggested that the papers of Kardashev, for example, have remained classics because they take theory as their compass. Thus, I proposed a toast to the theorists.
Deputy Minister Popovkin very kindly agreed to be photographed with me, and the image is below. Because I brought only one set of clothes to Baikonur, I am not particularly well dressed; but as one of our Russian hosts told me, not much is expected of an American.
Here is a Buran, the Soviet-era reusable space vehicle, similar to the shuttle, at the Baikonur space museum. It is slightly larger than the shuttle, and was launched on a larger rocket. It flew once in space, without human crew, as a test -- before the economic crisis attending the collapse of the Soviet Union ended the program. Actually ten were built, so this is not unique.
Here I am at the controls. This is the copilot seat.
Today we visited the museum of of Russian space flight at Baikonur. It's an impressive record of an active industry, dating back to before Sputnik and stretching to today. This involved a trip to the site to "plakata 0" where the original builders of the site stayed. This small cottage was used by Korolev, the first Chief Designer. A nearly identical cottage next door was used by Gagarin and his backup in the days before his historic flight.
This morning at 5:15 am local time, some of the other visitors and I watched a Proton booster launch, from the hotel. This rocket is larger than any commonly launched from the US nowadays; it is not the largest Russian rocket, but it's the largest in common use at present. It was carrying two satellites to geostationary orbit; one a communications satellite for Kazakhstan. The launch site is 60 km away for the hotel, but the show was impressive. Precisely on time, we saw a bright orange glow in the northeast, which faded briefly and then brightened again. A bright dot traveled up from the ground into the clouds. As we turned away, thinking that the show was over, we saw a contrail from the first stage through a hole in the clouds, as it dropped back to Earth. The bright dot of the second-stage traveled onward in a gentle curve to orbit. At the same moment, we heard a tremendous rumbling: sound had finally reached us from the launch site. As we watched, the exhaust from the second stage expanded to form a cloud, illuminated first in orange and then in brilliant white. Sunrise had taken place at the high altitude of the rocket, much earlier than at our spot on the ground. The cloud seemed like a small sun. It reminded me of the short story "Rocket Summer" by Ray Bradbury, in the Martian Chronicles, where the launch of an enormous rocket to Mars in wintertime in a small Ohio town produces a short but pleasant summer. In this case, we saw a short but brilliant dawn.
Today I traveled to Baikonur Cosmodrome in Kazakhstan, where I hope to watch the launch of the Radioastron spacecraft. A van picked me up in front of my hotel at 5 am, and dropped me with a group of astronomers outside the Akademishskaya Hotel. It was good to be back with a group of colleagues, nearly all familiar and most of them friends. A charter bus took us from there to Domodedovo Airport. We hit a snag at immigration: our visas allowed us to leave, but not return to Russia. Of course, officials had assured the scientists organizing the trip that we need not technically leave Russia, so that our single-entry visas would remain valid, but the officer at the immigration gate and his boss insisted on giving our visas the exit stamp. Many jokes about staying in Kazakhstan permanently followed. The institute in Moscow is working to correct the situation.
A TU-154 took us to the airstrip for Baikonur, a 3-hour flight. We sat in the first class section; seats were basic, but we were served an excellent meal with smoked salmon and sturgeon, cold cuts, candy, and baked salmon. The view was cloudy at first, but the overcast broke over Kazakhstan and we saw an enormous desert, broken with dry lakes and occasional creeks or rivers marked by bright green. A postdoc from Moscow said his father had been stationed at Baikonur while in the military, and that the river were full of large fish similar to carp. After an easy landing at the small airstrip, we disembarked into an oven. The temperature was said to be 41C, and it felt like 110F with absolutely no humidity. Kazakh customs and immigration was perfunctory, aside from a fair bit of paper shuffling and transfers of scientists and cargo. Quite a few of the officials looked very Asian, similar to Han Chinese. Indeed, we are not far from China here.
Our Russian colleagues went off to fill out even more forms, while the 8 foreign nationals went to the "Sputnik" hotel. We'd heard that the cost would be $567 per night, but after much haggling the manager agreed to a discounted rate of 280 Euros per night -- in cash and without internet access. The hotel was originally built to hold officials working on the Apollo-Soyuz linkup. It resembles a Best Western with nicer furnishings lovely woodwork, and old-fashioned toilet and shower.
Our group tried to obtain the needed cash at the Bank of Kazakhstan -- where they were unable to help us. Fortunately, I have plenty of cash, although I will have to get more in Moscow. Most interesting was the bank building, traditional construction with very thick walls and heavy doors. There was no air conditioning, but none was needed. We then enjoyed $1 beers at the cafe in the "Arbat" section of Baikonur. The cafe had a menu page listing the cost of breaking glassware and furniture, suggesting that this is not uncommon. Several cats lived in the cafe, enjoying scraps of shishkabob.
This "Arbat" is named after a bohemian district of Moscow, is a pedestrian mall where the locals enjoy walking and watching in the evening. The majority are clearly Kazakhs. They seem very cheerful and friendly, although we were warned not to walk alone in town. Ethnic tensions have produced problems; problems in the large cities have received coverage in the West. Most of the housing is apartment blocks about 3 stories tall. Most are in poor shape outside, with crumbling masonry; but no grafitti or vandalism. The yards between are dusty, with a few trees and plants, but children play.
Some kindly contractors helped me out with the internet and I am now back in touch!
Here I am with the Radioastron spacecraft, at the Lavochkin Association outside Moscow in 2009.