orbiter

Your mission

Convert a thruster force from pound-force into milli-newtons, and reject an invalid reading.

today's brief

September 1999. NASA's 327 million dollar Mars Climate Orbiter fires its engine to slip into orbit, then goes silent forever. The cause: Lockheed's software reported thruster force in pound-force, the NASA navigation code read those numbers as newtons, and nobody converted between the two. The probe came in at about 57 km above the surface instead of the planned 226, far too low to survive, and was never heard from again. You are the engineer who adds the one conversion everybody forgot.

See it in action

to_millinewtons(1)

Expected result

Your checklist

For your own tracking. Tests grade your code.

The force is given in pound-force.
One pound-force equals 4448 milli-newtons: return the converted value.
A negative force is not a valid reading: return -1.

More examples

to_millinewtons(25)

Expected result

to_millinewtons(-2)

Expected result

-1

Constraints

Expected files

impulse.c

Allowed functions

None. Write every helper yourself.

Back to compete

Solutions

orbiter

Your mission

Convert a thruster force from pound-force into milli-newtons, and reject an invalid reading.

today's brief

See it in action

to_millinewtons(1)

Expected result

Your checklist

For your own tracking. Tests grade your code.

The force is given in pound-force.
One pound-force equals 4448 milli-newtons: return the converted value.
A negative force is not a valid reading: return -1.

More examples

to_millinewtons(25)

Expected result

to_millinewtons(-2)

Expected result

-1

Constraints

Expected files

impulse.c

Allowed functions

None. Write every helper yourself.

Back to compete

Solutions