QUESTION 2

Consider the query: NASA Atlantis Orbit launch.

Rank D1-D3 with respect to this query using:

Log tf weighting

Idf weight

Tfidf weight.

How does the ranking change? We provided word counts for you.

Please show the formulae you used and show your work. Answers that consist only of numeric results will get no credit.

D1: Shuttle Update for June 22

Fri, 22 Jun 2012 03:28:16 PM EDT

Shuttle Atlantis: In Orbiter Processing Facility-1 at NASAs Kennedy Space Center in Florida, technicians completed the re-installation of shuttle Atlantis orbital maneuvering system, or OMS, pods this week. The OMS provided the shuttle with thrust for orbit insertion, rendezvous and deorbit. Atlantis Replica Shuttle Main Engines are scheduled to be installed next week. Atlantis is being prepared for public display at the Kennedy Space Center Visitor Complex and is scheduled to roll over to the complex in November. The Kennedy Space Center Visitor Complex is targeting a July 2013 grand opening for Atlantis new home. Shuttle Endeavour: In Orbiter Processing Facility-2, space shuttle Endeavours payload bay doors were closed for the final time on Tuesday, June 19. Endeavour is being prepared for public display at the California Science Center in Los Angeles. Its ferry flight to California is targeted for mid-September. (Source: www.nasa.gov/shuttle/)

Number of words in D1: 150

Number of occurrences of NASA: 1

Number of occurrences of Atlantis: 5

Number of occurrences of Orbit (including Orbiter, deorbit, orbital): 5

Number of occurrences of launch (including launching): 0

D2: The Space Shuttle was a partially reusable launch system and orbital spacecraft operated by the U.S. National Aeronautics and Space Administration (NASA) for human spaceflight missions. The system combined rocket launch, orbital spacecraft, and re-entry spaceplane with modular add-ons. The first of four orbital test flights occurred in 1981 leading to operational flights beginning in 1982. It was used on a total of 135 missions from 1981 to 2011 all launched from the Kennedy Space Center, Florida.

Major missions included launching numerous satellites, interplanetary probes, the Hubble Space Telescope (HST), conducting space science experiments, and constructing and servicing the International Space Station. Major components included the orbiters, recoverable boosters, external tanks, payloads, and supporting infrastructure. Five space-worthy orbiters were built; two were destroyed in mission accidents. (source: Wikipedia)

Number of words in D2: 126

Number of occurrences of NASA: 1

Number of occurrences of Atlantis: 0

Number of occurrences of orbit (including Orbiter, deorbit, orbital): 5

Number of occurrences of launch (including launching): 4

D3: NASA's Space Shuttle program, officially called Space Transportation System (STS), was the United States government's manned launch vehicle program from 1981 to 2011. The winged Space Shuttle orbiter was launched vertically, usually carrying four to seven astronauts (although eight have been carried) and up to 50,000 lb (22,700 kg) of payload into low Earth orbit (LEO). When its mission was complete, the Shuttle could independently move itself out of orbit using its Maneuvering System (it oriented itself appropriately and fired its main OMS engines, thus slowing it down) and re-enter the Earth's atmosphere. During descent and landing the orbiter acted as a re-entry vehicle and a glider, using its OMS system and flight surfaces to make adjustments.

The shuttle is the only winged manned spacecraft to have achieved orbit and land, and the only reusable space vehicle that has ever made multiple flights into orbit. (Source: Wikipedia)

Number of words in D3: 145

Number of occurrences of NASA: 1

Number of occurrences of Atlantis: 0

Number of occurrences of orbit (including Orbiter, deorbit, orbital): 6

Number of occurrences of launch (including launching): 2

Assume that these are all the documents in the corpus.