UPSC Prelims Practice Questions — ISRO flew NVS-03 satellite with pyro valves open: chief

Q1. With reference to India's satellite-based navigation systems NavIC and GAGAN, consider the following statements: Which of the statements given above is/are correct?

  1. GAGAN works by sending corrections and integrity information for GPS signals, so it cannot give a fix when GPS satellites are unavailable.
  2. A NavIC receiver within the service area can compute its position even when no GPS satellite is in view.
  3. Like GAGAN, NavIC was designed mainly to improve the accuracy and integrity of GPS fixes for aircraft.
  • A. 2 and 3 only
  • B. 1 and 3 only
  • C. 1 and 2 only
  • D. 1, 2 and 3

Q2. Consider the following facts about NavIC: I. Its primary service area covers India and a region up to about 1,500 km beyond India's boundary. II. It offers a Standard Positioning Service for civilian users and an encrypted Restricted Service only for authorised users. III. Its constellation combines geostationary (GEO) satellites with geosynchronous satellites in inclined orbits (GSO). Which of the following inferences can validly be drawn from the above facts?

  1. An Indian scientist at a research station in Antarctica cannot rely on NavIC alone for positioning.
  2. Because all its satellites are geosynchronous, every NavIC satellite stays fixed at one point in the sky as seen from India.
  3. Authorised strategic users in the service area can get a positioning signal that others cannot freely decode.
  4. Since NavIC exists, GPS augmentation systems are no longer needed for aircraft navigation over India.
  • A. 2 and 4 only
  • B. 1 and 3 only
  • C. 1, 2 and 3 only
  • D. 1, 3 and 4 only

Q3. The second-generation NVS navigation satellites add an L1-band signal to NavIC's existing L5 and S-band signals. In this context, consider the following statements: Which of the statements given above is/are correct?

  1. Because L1 is also used by GPS and Galileo, NavIC can be added to mass-market receiver chips with fewer hardware changes.
  2. Once the L1 signal is added, the NVS satellites stop transmitting the older L5 and S-band signals.
  3. Adding the L1 band extends NavIC's coverage from a regional service to a global service.
  • A. 2 and 3 only
  • B. 1, 2 and 3
  • C. 1 and 2 only
  • D. 1 only

Q4. Consider the following statements: Which of the following is correct in respect of the above statements?

  1. A navigation satellite whose atomic clocks have failed can stay in its correct orbital slot yet be of no use for positioning.
  2. A navigation satellite's atomic clock also controls the thrusters that keep the satellite in its orbital slot.
  • A. Both Statement-I and Statement-II are correct and Statement-II explains Statement-I
  • B. Both Statement-I and Statement-II are correct, but Statement-II does not explain Statement-I
  • C. Statement-I is correct, but Statement-II is incorrect
  • D. Statement-I is incorrect, but Statement-II is correct

Q5. After the launch of NVS-03, ISRO reported that the satellite reached a perigee of 170.31 km against a planned 170.36 km and an apogee of 38,080 km against a planned 37,247 km, and described the flight as highly accurate. Which of the following inferences can validly be drawn from the above?

  1. Because the apogee is higher than planned, the satellite has escaped Earth's gravity and cannot be placed in its slot.
  2. The satellite is still in an elliptical transfer orbit and must use its own propulsion to reach its geosynchronous slot.
  3. Because the perigee almost exactly matched plan, the satellite is already in its final operational orbit.
  • A. 2 only
  • B. 1 only
  • C. 1 and 3 only
  • D. 2 and 3 only

Q6. NavIC's constellation combines geostationary (GEO) satellites with geosynchronous satellites in inclined orbits (GSO). In this context, consider the following statements: Which of the statements given above is/are correct?

  1. Every geostationary satellite is geosynchronous, but a geosynchronous satellite need not be geostationary.
  2. A geosynchronous satellite in an inclined orbit completes one revolution in less time than a geostationary satellite.
  • A. 1 only
  • B. 2 only
  • C. Both 1 and 2
  • D. Neither 1 nor 2

Q7. Consider the following statements: Which of the following is correct in respect of the above statements?

  1. Giving a pyro valve a redundant (backup) electrical firing path guarantees that no single connector fault can stop the valve from firing.
  2. ISRO found that the most likely cause of the NVS-02 orbit-raising failure was the disengagement of contacts in both the main and the redundant paths of a connector.
  • A. Both Statement-I and Statement-II are correct and Statement-II explains Statement-I
  • B. Both Statement-I and Statement-II are correct, but Statement-II does not explain Statement-I
  • C. Statement-I is correct, but Statement-II is incorrect
  • D. Statement-I is incorrect, but Statement-II is correct

Q8. Consider the following assertion: Flying NVS-03 with its pyro valves already open removed a single point of failure from the satellite's orbit-raising sequence. Which of the following statements support/supports the above assertion?

  1. NVS-02 reached its transfer orbit, showing that its launch vehicle had performed normally.
  2. In NVS-02, the signal to fire the oxidiser-line pyro valve was lost because contacts came loose in a connector carrying both the main and redundant paths.
  3. A pyro valve is a one-time device opened by a small explosive charge, so a valve that is already open needs no firing signal in flight.
  • A. 1 and 2 only
  • B. 2 and 3 only
  • C. 1 and 3 only
  • D. 1, 2 and 3