They don't have an A record for nasa.gov. For those who don't have dig (or don't care enough to do an actual DNS request and would rather trust some other, lesser tool):

  $ dig nasa.gov

  ; <<>> DiG 9.6.1-P2-RedHat-9.6.1-7.P2.fc11 <<>> nasa.gov
  ;; global options: +cmd
  ;; Got answer:
  ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 40211
  ;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 0

  ;; QUESTION SECTION:
  ;nasa.gov.                      IN      A

  ;; AUTHORITY SECTION:
  nasa.gov.               300     IN      SOA     ns1.nasa.gov. dns.nasa.gov. 2008043229 10800 1200 3600000 14400

No A records.

  $ dig www.nasa.gov

  ; <<>> DiG 9.6.1-P2-RedHat-9.6.1-7.P2.fc11 <<>> www.nasa.gov
  ;; global options: +cmd
  ;; Got answer:
  ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 22541
  ;; flags: qr rd ra; QUERY: 1, ANSWER: 5, AUTHORITY: 9, ADDITIONAL: 0

  ;; QUESTION SECTION:
  ;www.nasa.gov.                  IN      A

  ;; ANSWER SECTION:
  www.nasa.gov.           300     IN      CNAME   www.nasa.gov.speedera.net.
  www.nasa.gov.speedera.net. 120  IN      CNAME   www.nasa.gov.edgesuite.net.
  www.nasa.gov.edgesuite.net. 21600 IN    CNAME   a1718.x.akamai.net.
  a1718.x.akamai.net.     20      IN      A       64.81.79.72
  a1718.x.akamai.net.     20      IN      A       64.81.79.70

Looks like the whole site is served through Akamai too.

What's a "direct @ url" ? Now we're overloading the @ for something else too?

@ in a BIND zone file refers to the domain defined at the top of the file.

It's been awhile since I've written one, so go look at Wikipedia:

http://en.wikipedia.org/wiki/Zone_file

By saying that it's not working, you assume that a raw domain.com is "broken" if it doesn't resolve to an address which is presumably the same as www.domain.com, which is pretty much baseless. There's no technical reason for a bare domain to resolve to anything, it's just a popular convention to make it redirect to www.domain.com because most people who type that into a browser expect your web site to come up.

Why not just add a CNAME for convenience? Who knows. They may have an internal technical reason, or it may just be a case of "don't do something unnecessary just because it's easy". For what it's worth, government agencies have a pretty good variety - army.mil and navy.mil both have the same behavior as nasa.gov, whitehouse.gov and justice.gov both have redirects to the "canonical" www url and house.gov and senate.gov both serve the same content as their www versions without a redirect either way.

Regardless of their particular reason, I see no cause to assume that it's due to laziness, funding level or how "high-tech" they are. It's just a convention that they don't use, but you expect.

It is "broken." You're right that "it's just a convention that they don't use, but you expect." But it's a convention that must prevent a handful of people from accessing their website each day, or at least causing them to Google "NASA" in confusion. There's no valid technical reason for doing this. It's a serious usability/findability fail.

Although a smaller scale, the Australian Bureau of Meteorology has the same problem. bom.gov.au doesn't resolve to anything.

For what it's worth, Firefox will change nasa.gov to www.nasa.gov.au but won't do the same for bom.gov.au. Internet Explorer won't do this at all.

I recall a time (late '90s) when microsoft.com was similarly afflicted. Seriously. That was back when everyone instinctively typed "www," though.

In this case, I'm sure it's a temporary glitch.

They must have heard you. Works fine using nasa.gov

EDIT: using firefox. What browser are you using?

I think that's your browser adding the www in. Try it in Internet Explorer or try pinging nasa.gov

This is part of a really old host-naming convention from when a domain name's usage wasn't 99.999% web. So people would relegate their world wide web servers out to www.<theirdomain>.