Haskell tools for satellite operations

At last week's CUFP I did a talk called “Haskell tools for satellite operations”. The abstract is:

Since 2013-04 the presenter has been supporting SSC (the Swedish Space Corporation) in operating the telecommunications satellite “Sirius 3” from its Mission Control Center in Kiruna. Functions in the satellite vendor's operations software are breaking down as the orbit of the ageing satellite degrades. To fill in the gaps in software capabilities the presenter has developed several operational tools using Haskell.

The talk will give an overview of the satellite operations environment, the tools developed in Haskell, how they benefitted (and occasionally suffered) from the choice of implementation language, which (public) libraries were critical to their success, and how they were deployed in the satellite operations environment.

A video recording of the talk is available on the CUFP page for the talk and on youtube.

If this interests you be sure to check out the other talk from the “Functional programming in space!” track; Michael Oswald's Haskell in the Misson Control Domain.

Numtype(-tf) and dimensional(-tf) updated for GHC 7.8.1

My numtype and numtype-tf libraries both needed one line changes to be compatible with the GHC 7.8.1 release candidate. Versions 1.1 and 0.1.2 (respectively) have been uploaded to hackage.

The update to numtype also necessitated an update to dimensional, mainly to bump the upper bounds of the numtype dependency, but a few API additions snuck in too. The change log for the new version (0.12.3), as well as the other versions that have been uploaded to hackage since my previous version announcement can be found at the bottom of this post.

Dimensional-tf didn’t need an update for GHC 7.8 but has been updated with the same API additions as dimensional.

Dimensional’s changelog

0.13 (2014-02)

• Bump numtype dependency to 1.1 (GHC 7.8.1 compatibility fix).
• Added Torque.
• Added D.. for the type synonym quantities (e.g., Angle).

0.12.2 (2013-11)

• Added FirstMassMoment, MomentOfInertia, AngularMomentum.
• Improved unit numerics.

0.12.1 (2013-07)

• Typeable Dimensionals.

0.12 (2013-06)

• Polymorphic _0 (closes issue 39).
• Added astronomicalUnit.
• Added imperial volume units.
• Added ‘mil’ (=inch/1000).
• Added tau.
• Added KinematicViscosity.

0.10.1.2 (2011-09)

• Bumped time dependency to < 1.5.

0.10.1.2 (2011-08)

• Bumped time dependency to < 1.4.

0.10.1 (2011-08)

GHC 7.2.1 compatibility fix:

• Increased CGS context-stack to 30.

Joy and caution with -XNegativeLiterals in GHC 7.8

The new NegativeLiterals extension in GHC 7.8 scratches an itch I have had for a long time. Namely:

> y = (-41940.917505092) *~ kilo meter

With NegativeLiterals users of dimensional can finally write:

> y = -41940.917505092 *~ kilo meter

Thanks GHC HQ and contributors!

However, be careful so the extension doesn’t break your calculations. Here is an example (not using dimensional) of how you could get bitten. Without NegativeLiterals:

> Prelude> -2 ^ 2
> -4

With NegativeLiterals:

> Prelude> -2 ^ 2
> 4

I certainly prefer the latter behaviour, but having some regression tests in place when enabling NegativeLiterals might be a good idea.