BERLIN -- The European Space Agency says its Philae lander has made contact again after a five-day gap as mission controllers work to improve communications with the washing machine-sized spacecraft on a speeding comet.

Philae, which in November became the first spacecraft to land on a comet, sent its first signals in seven months last Saturday. As the comet approaches the sun, Philae's solar panels are getting enough light to revive the lander.

Philae sent more signals on Sunday but wasn't heard from again until Friday, a gap ESA says wasn't unexpected. In a pair of two-minute contacts 17 minutes apart, it delivered more housekeeping and status data.

ESA has sent commands to the lander's mother ship Rosetta, 180 kilometres (112 miles) from the comet, to improve communications between the spacecraft.