Deep space network

I was discussing with a friend of mine about why early pictures of moon, say from the apollo missions, were so blurry. Well, astronomers don't enjoy the kind of speeds you and I do every day on our mobile phones, laptops and desktops. Most of us get impatient about low internet speeds, curse our service if the internet connection changes from 3G/H/H+to 2G. On the other hand, the data transmission rate from space craft back to earth is in the range of 100s of kbps. Deep space network, the title of this post, is a collection of radio antenna distributed all over the earth which are used to communicate with space craft and DSN NOW is a site which shows which antenna is communicating with which satellite, what the transmission rate is, what frequency they are transmitting at and so on. There are a lot more satellites than there are antenna so i guess data is pulled from the satellites based on demand or maybe periodically. As of now, MAVEN, the NASA mars mission is operating at a data rate of ~500 kbps.  On the other hand, MOM, the ISRO mars mission is operating at a 999 bites per second. You can check it yourself. Before i comment on the large different in data rates, I shall check a couple more times to see if this is a temporary rate of transmission. Coming back to the point, I hope you can understand now why the images from the Apollo are grainy. In fact, in efforts to increase this data transmission rate from space, NASA scientists have developed OPALS, an instrument on the ISS which can communicate with a base station on earth using lasers and were successful in communicating with the ISS for over 2 minutes while reaching a maximum data transmission rate of 50 mbps! With those speeds, astronauts can finally buffer youtube videos and watch netflix movies with ease!

Popular posts from this blog

Animation using GNUPlot

Image
Animation using GNUPlot I've been trying to create an animation depicting a quasar spectrum moving across the 5 SDSS pass bands with respect to redshift. It is important to visualise what emission lines are moving in and out of bands to be able to understand the color-redshift plots and the changes in it. I've tried doing this using the animate function in matplotlib, python but i wasn't able to make it work - meaning i worked on it for a couple of days and then i gave up, not having found solutions for my problems on the internet. And then i came across this site, where the gunn-peterson trough and the lyman alpha forest have been depicted - in a beautiful manner. And this got me interested in using js and d3 to do the animations and make it dynamic - using sliders etc. In the meanwhile, i thought i'd look up and see if there was a way to create animations in gnuplot and whoopdedoo, what do i find but nirvana! In the image, you see 5 static curv
Read more

Arxiv author affiliations using Python

So, I wanted to get author affiliation information from papers on arXiv. arXiv provides with an API to bulk query their database and get information. Following that, I look for the attribute 'arxiv:affiliation' in the html data. Here's the code - import urllib from BeautifulSoup import BeautifulStoneSoup   url = 'http://export.arxiv.org/api/query?search_query=all:astro&start=0&max_results=1000'   data = urllib.urlopen(url).read() soup = BeautifulStoneSoup(data) #print(soup.prettify()) #list = soup.findAll('arxiv:affiliation') #for i in range(len(list)): #        print list[i].contents   test = [tag.string for tag in soup.findAll('arxiv:aiffiliation')] Now, the problem I'm having is that I'm getting affiliation of all authors which I want to split into sets of affiliations of authors of a paper, which I'm stuck on at the moment. Once I get that part, I can move on to the next part of this pet project, displaying these
Read more

Thoughts on the National Deep Tech Startup Policy

The Principal Scientific Advisor to the Government of India published a draft policy to support and nurtue the unique requirements of Deep Tech startups in India. I just finished reading it and put together a few comments in a FOSS United forum thread . I will probably read it again a week or so later and try to update my comments on the thread with any new insights/thoughts I have.
Read more